LHC to re-awaken in 2015 with doubled energy, luminosity

This article, as written by me, appeared in The Hindu on January 10, 2012.

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After a successful three-year run that saw the discovery of a Higgs-boson-like particle in early 2012, the Large Hadron Collider (LHC) at CERN, near Geneva, Switzerland, will shut down for 18 months for maintenance and upgrades.

This is the first of three long shutdowns, scheduled for 2013, 2017, and 2022. Physicists and engineers will use these breaks to ramp up one of the most sophisticated experiments in history even further.

According to Mirko Pojer, Engineer In-charge, LHC-operations, most of these changes were planned in 2011. They will largely concern fixing known glitches on the ATLAS and CMS particle-detectors. The collider will receive upgrades to increase its collision energy and frequency.

Presently, the LHC smashes two beams, each composed of precisely spaced bunches of protons, at 3.5-4 tera-electron-volts (TeV) per beam.

By 2015, the beam energy will be pushed up to 6.5-7 TeV per beam. Moreover, the bunches which were smashed at intervals of 50 nanoseconds will do so at 25 nanoseconds.

After upgrades, “in terms of performance, the LHC will deliver twice the luminosity,” Dr. Pojer noted in an email to this Correspondent, with reference to the integrated luminosity. Precisely, it is the number of collisions that the LHC can deliver per unit area which the detectors can track.

The instantaneous luminosity, which is the luminosity per second, will be increased to 1x10³⁴ per centimetre-squared per second, ten-times greater than before, and well on its way to peaking at 7.73x10³⁴ per centimetre-squared per second by 2022.

As Steve Myers, CERN’s Director for Accelerators and Technology, announced in December 2012, “More intense beams mean more collisions and a better chance of observing rare phenomena.” One such phenomenon is the appearance of a Higgs-boson-like particle.

The CMS experiment, one of the detectors on the LHC-ring, will receive some new pixel sensors, a technology responsible for tracking the paths of colliding particles. To make use of the impending new luminosity-regime, an extra layer of these advanced sensors will be inserted around a smaller beam pipe.

If results from it are successful, CMS will receive the full unit in late-2016.

In the ATLAS experiment, unlike with CMS which was built with greater luminosities in mind, pixel sensors are foreseen to wear out within one year after upgrades. As an intermediate solution, a new layer of sensors called the B-layer will be inserted within the detector for until 2018.

Because of the risk of radiation damage due to more numerous collisions, specific neutron shields will be fit, according to Phil Allport, ATLAS Upgrade Coordinator.

Both ATLAS and CMS will also receive evaporative cooling systems and new superconducting cables to accommodate the higher performance that will be expected of them in 2015. The other experiments, LHCb and ALICE, will also undergo inspections and upgrades to cope with higher luminosity.

An improved failsafe system will be installed and the existing one upgraded to prevent accidents such as the one in 2008.

Then, an electrical failure damaged 29 magnets and leaked six tonnes of liquid helium into the tunnel, precipitating an eight-month shutdown.

Generally, as Martin Gastal, CMS Experimental Area Manager, explained via email, “All sub-systems will take the opportunity of this shutdown to replace failing parts and increase performance when possible.”

All these changes have been optimised to fulfil the LHC’s future agenda. This includes studying the properties of the newly discovered particle, and looking for signs of new theories of physics like supersymmetry and higher dimensions.

(Special thanks to Achintya Rao, CMS Experiment.)

The case of the red-haired kids

This blog post first appeared, as written by me, on The Copernican science blog on December 30, 2012.

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Seriously, shame on me for not noticing the release of a product named Correlate until December 2012. Correlate by Google was released in May last year and is a tool to see how two different search trends have panned out over a period of time. But instead of letting you pick out searches and compare them, Correlate saves a bit of time by letting you choose one trend and then automatically picks out trends similar to the one you’ve your eye on.

For instance, I used the “Draw” option and drew a straight, gently climbing line from September 19, 2004, to July 24, 2011 (both randomly selected). Next, I chose “India” as the source of search queries for this line to be compared with, and hit “Correlate”. Voila! Google threw up 10 search trends that varied over time just as my line had.



Since I’ve picked only India, the space from which the queries originate remains fixed, making this a temporal trend - a time-based one. If I’d fixed the time - like a particular day, something short enough to not produce strong variations - then it’d have been a spatial trend, something plottable on a map.

Now, there were a lot of numbers on the results page. The 10 trends displayed in fact were ranked according to a particular number “r” displayed against them. The highest ranked result, “free english songs”, had r = 0.7962. The lowest ranked result, “to 3gp converter”, had r = 0.7653.



And as I moused over the chart itself, I saw two numbers, one each against the two trends being tracked. For example, on March 1, 2009, the “Drawn Series” line had a number +0.701, and the “free english songs” line had a number -0.008, against it.



What do these numbers mean?

This is what I want to really discuss because they have strong implications on how lay people interpret data that appears in the context of some scientific text, like a published paper. Each of these numbers is associated with a particular behaviour of some trend at a specific point. So, instead of looking at it as numbers and shapes on a piece of paper, look at it for what it represents and you’ll see so many possibilities coming to life.

The numbers against the trends, +0.701 for “Drawn Series” (my line) and -0.008 for “free english songs” in March ‘09, are the deviations. The deviation is a lovely metric because it sort of presents the local picture in comparison to the global picture, and this perspective is made possible by the simple technique used to evaluate it.

Consider my line. Each of the points on the line has a certain value. Use this information to find their average value. Now, the deviation is how much a point’s value is away from the average value.

It’s like if 11 red-haired kids were made to stand in a line ordered according to the redness of their hair. If the “average” colour around was a perfect orange, then the kid with the “reddest” hair and the kid with the palest-red hair will be the most deviating. Kids with some semblance of orange in their hair-colour will be progressively less deviating until they’re past the perfect “orangeness”, and the kid with perfectly-orange hair will completely non-deviating.

So, on August 23, 2009, “Drawn Series” was higher than its average value by 0.701 and “free english songs” was lower than its average value by 0.008. Now, if you’re wondering what the units are to measure these numbers: Deviations are dimensionless fractions - which means they’re just numbers whose highness or lowness are indications of intensity.

And what’re they fractions of? The value being measured along the trend being tracked.

Now, enter standard deviation. Remember how you found the average value of a point on my line? Well, the standard deviation is the average value among all deviations. It’s like saying the children fitting a particular demographic are, for instance, 25 per cent smarter on average than other normal kids: the standard deviation is 25 per cent and the individual deviations are similar percentages of the “smartness” being measured.

So, right now, if you took the bigger picture, you’d see the chart, the standard deviation (the individual deviations if you chose to mouse-over), the average, and that number “r”. The average will indicate the characteristic behaviour of the trend - let’s call it “orange” - the standard deviation will indicate how far off on average a point’s behaviour will be deviating in comparison to “orange” - say, “barely orange”, “bloody”, etc. - and the individual deviations will show how “orange” each point really is.

At this point I must mention that I conveniently oversimplified the example of the red-haired kids to avoid a specific problem. This problem has been quite single-handedly responsible for the news-media wrongly interpreting results from the LHC/CERN on the Higgs search.

In the case of the kids, we assumed that, going down the line, each kid’s hair would get progressively darker. What I left out was how much darker the hair would get with each step.

Let’s look at two different scenarios.

Scenario 1: The hair gets darker by a fixed amount each step.

Let’s say the first kid’s got hair that’s 1 units of orange, the fifth kid’s got 5 units, and the 11th kid’s got 11 units. This way, the average “amount of orange” in the lineup is going to be 6 units. The deviation on either side of kid #6 is going to increase/decrease in steps of 1. In fact, from the first to the last, it’s going to be 5, 4, 3, 2, 1, 0, 1, 2, 3, 4, and 5. Straight down and then straight up.



Scenario 2: The hair gets darker slowly and then rapidly, also from 1 to 11 units.

In this case, the average is not going to be 6 units. Let’s say the “orangeness” this time is 1, 1.5, 2, 2.5, 3, 3.5, 4, 5.5, 7.5, 9.75, and 11 per kid, which brings the average to ~4.6591 units. In turn, the deviations are 3.6591, 3.1591, 2.6591, 2, 1591, 1.6591, 1.1591, 0.6591, 0.8409, 2.8409, 5.0909, and 6.3409. In other words, slowly down and then quickly more up.



In the second scenario, we saw how the average got shifted to the left. This is because there were more less-orange kids than more-orange ones. What’s more important is that it didn’t matter if the kids on the right had more more-orange hair than before. That they were fewer in number shifted the weight of the argument away from them!

In much the same way, looking for the Higgs boson from a chart that shows different peaks (number of signature decay events) at different points (energy levels), with taller but fewer peaks to one side and shorter but many more peaks to the other, can be confusing. While more decays could’ve occurred at discrete energy levels, the Higgs boson is more likely (note: not definitely) to be found within the energy-level where decays occur more frequently (in the chart below, decays are seen to occur more frequently at 118-126 GeV/c2 than at 128-138 GeV/c2 or 110-117 GeV/c2).

[caption id="attachment_24766" align="aligncenter" width="750"] Idea from Prof. Matt Strassler's blog[/caption]

If there’s a tall peak where a Higgs isn’t likely to occur, then that’s an outlier, a weirdo who doesn’t fit into the data. It’s probably called an outlier because its deviation from the average could be well outside the permissible deviation from the average.

This also means it’s necessary to pick the average from the right area to identify the right outliers. In the case of the Higgs, if its associated energy-level (mass) is calculated as being an average of all the energy levels at which a decay occurs, then freak occurrences and statistical noise are going to interfere with the calculation. But knowing that some masses of the particle have been eliminated, we can constrain the data to between two energy levels, and then go after the average.

So, when an uninformed journalist looks at the data, the taller peaks can catch the eye, even run away with the ball. But look out for the more closely occurring bunches - that’s where all the action is!

If you notice, you’ll also see that there are no events at some energy levels. This is where you should remember that uncertainty cuts both ways. When you’re looking at a peak and thinking “This can’t be it; there’s some frequency of decays to the bottom, too”, you’re acknowledging some uncertainty in your perspective. Why not acknowledge some uncertainty when you’re noticing absent data, too?

While there’s a peak at 126 GeV/c2, the Higgs weighs between 124-125 GeV/c2. We know this now, so when we look at the chart, we know we were right in having been uncertain about the mass of the Higgs being 126 GeV/c2. Similarly, why not say “There’s no decays at 113 GeV/c2, but let me be uncertain and say there could’ve been a decay there that’s escaped this measurement”?

Maybe this idea’s better illustrated with this chart.



There’s a noticeable gap between 123 and 125 GeV/c2. Just looking at this chart and you’re going to think that with peaks on either side of this valley, the Higgs isn’t going to be here… but that’s just where it is! So, make sure you address uncertainty when you’re determining presences as well as absences.

So, now, we’re finally ready to address “r”, the Pearson covariance coefficient. It’s got a formula, and I think you should see it. It’s pretty neat.



(TeX: r\quad =\quad \frac { { \Sigma }_{ i=1 }^{ n }({ X }_{ i }\quad -\quad \overset { \_ }{ X } )({ Y }_{ i }\quad -\quad \overset { \_ }{ Y } ) }{ \sqrt { { \Sigma }_{ i=1 }^{ n }{ ({ X }_{ i }\quad -\quad \overset { \_ }{ X } ) }^{ 2 } } \sqrt { { \Sigma }_{ i=1 }^{ n }{ (Y_{ i }\quad -\quad \overset { \_ }{ Y } ) }^{ 2 } } })

The equation says "Let's see what your Pearson covariance, "r", is by seeing how much all of your variations are deviant keeping in mind both your standard deviations."

The numerator is what’s called the covariance, and the denominator is basically the product of the standard deviations. X-bar, which is X with a bar atop, is the average value of X - my line - and the same goes for Y-bar, corresponding to Y - “mobile games”. Individual points on the lines are denoted with the subscript “i”, so the points would be X1, X2, X3, ..., and Y1, Y2, Y3, …”n” in the formula is the size of the sample - the number of days over which we’re comparing the two trends.

The Pearson covariance coefficient is not called the Pearson deviation coefficient, etc., because it normalises the graph’s covariance. Simply put, covariance is a measure of how much the two trends vary together. It can have a minimum value of 0, which would mean one trend’s variation has nothing to do with the other’s, and a maximum value of 1, which would mean one trend’s variation is inescapably tied with the variation of the other’s. Similarly, if the covariance is positive, it means that if one trend climbs, the other would climb, too. If the covariance is negative, then one trend’s climbing would mean the other’s descending (In the chart below, between Oct ’09 and Jan ’10, there’s a dip: even during the dive-down, the blue line is on an increasing note – here, the local covariance will be negative).



Apart from being a conveniently defined number, covariance also records a trend’s linearity. In statistics, linearity is a notion that stands by its name: like a straight line, the rise or fall of a trend is uniform. If you divided up the line into thousands of tiny bits and called each one on the right the “cause” and the one on the left the “effect”, then you’d see that linearity means each effect for each cause is either an increase or a decrease by the same amount.

Just like that, if the covariance is a lower positive number, it means one trend’s growth is also the other trend’s growth, and in equal measure. If the covariance is a larger positive number, you’d have something like the butterfly effect: one trend moves up by an inch, the other shoots up by a mile. This you’ll notice is a break from linearity. So if you plotted the covariance at each point in a chart as a chart by itself, one look will tell you how the relationship between the two trends varies over time (or space).

When must science give way to religion?

When I saw an article titled 'Sometimes science must give way to religion' in Nature on August 22, 2012, by Daniel Sarewitz, I had to read it. I am agnostic, and I try as much as I can to keep from attempting to proselyte anyone - through argument or reason (although I often fail at controlling myself). However, titled as it was, I had to read the piece, especially since it'd appeared in a publication I subscribe to for their hard-hitting science news, which I've always approached as Dawkins might: godlessly.

First mistake.

[caption id="attachment_23913" align="aligncenter" width="627"] Dr. Daniel Sarewitz[/caption]

At first, if anything, I hoped the article would treat the entity known as God as simply an encapsulation of the unknown rather than in the form of an icon or elemental to be worshiped. However, the lead paragraph was itself a disappointment - the article was going to be about something else, I understood.

Visitors to the Angkor temples in Cambodia can find themselves overwhelmed with awe. When I visited the temples last month, I found myself pondering the Higgs boson — and the similarities between religion and science.

The awe is architectural. When pilgrims visit a temple built like the Angkor, the same quantum of awe hits them as it does an architect who has entered a Pritzker-prize winning building. But then, this sort of "reasoning", upon closer observation or just an extra second of clear thought, is simply nitpicking. It implies that I'm just pissed that Nature decided to publish an article and disappoint ME. So, I continued to read on.

Until I stumbled upon this:

If you find the idea of a cosmic molasses that imparts mass to invisible elementary particles more convincing than a sea of milk that imparts immortality to the Hindu gods, then surely it’s not because one image is inherently more credible and more ‘scientific’ than the other. Both images sound a bit ridiculous. But people raised to believe that physicists are more reliable than Hindu priests will prefer molasses to milk. For those who cannot follow the mathematics, belief in the Higgs is an act of faith, not of rationality.

For a long time, I have understood that science and religion have a lot in common: they're both frameworks that are understood through some supposedly indisputable facts, the nuclear constituents of the experience born from believing in a world reality that we think is subject to the framework. Yes, circular logic, but how are we to escape it? The presence of only one sentient species on the planet means a uniform biology beyond whose involvement any experience is meaningless.

So how are we to judge which framework is more relevant, more meaningful? To me, subjectively, the answer is to be able to predict what will come, what will happen, what will transpire. For religion, these are eschatological and soteriological considerations. As Hinduism has it: "What goes around comes around!" For science, these are statistical and empirical considerations. Most commonly, scientists will try to spot patterns. If one is found, they will go about pinning the pattern's geometric whims down to mathematical dictations to yield a parametric function. And then, parameters will be pulled out of the future and plugged into the function to deliver a prediction.

Earlier, I would have been dismissive of religion's "ability" to predict the future. Let's face it, some of those predictions and prophecies are too far into the future to be of any use whatsoever, and some other claims are so ad hoc that they sound too convenient to be true... but I digress. Earlier, I would've been dismissive, but after Sarewitz's elucidation of the difference between rationality and faith, I am prompted to explain why, to me, it is more science than religion that makes the cut. Granted, both have their shortcomings: empiricism was smashed by Popper, while statistics and unpredictability are conjugate variables.

(One last point on this matter: If Sarewitz seems to suggest that the metaphorical stands in the way of faith evolving into becoming a conclusion of rationalism, then he also suggests lack of knowledge in one field of science merits a rejection of scientific rationality in that field. Consequently, are we to stand in eternal fear of the incomprehensible, blaming its incomprehensibility on its complexity? He seems to have failed to realize that a submission to the simpler must always be a struggle, never a surrender.)

Sarewitz ploughed on, and drew a comparison more germane and, unfortunately, more personal than logical.

By contrast, the Angkor temples demonstrate how religion can offer an authentic personal encounter with the unknown. At Angkor, the genius of a long-vanished civilization, expressed across the centuries through its monuments, allows visitors to connect with things that lie beyond their knowing in a way that no journalistic or popular scientific account of the Higgs boson can. Put another way, if, in a thousand years, someone visited the ruins of the Large Hadron Collider, where the Higgs experiment was conducted, it is doubtful that they would get from the relics of the detectors and super­conducting magnets a sense of the subatomic world that its scientists say it revealed.

Granted, if a physicist were to visit the ruins of the LHC, he may be able to put two and two together at the sight of the large superconducting magnets, striated with the shadows of brittle wires and their cryostatic sleeves, and guess the nature of the prey. At the same time, an engagement with the unknown at the Angkor Wat (since I haven't been there, I'll extrapolate my experience at the Thillai Nataraja Temple, Chidambaram, South India, from a few years back) requires a need to engage with the unknown. A pilgrim visiting millennia-old temples will feel the same way a physicist does when he enters the chamber that houses the Tevatron! Are they not both pleasurable?

I think now that what Sarewitz is essentially arguing against is the incomparability of pleasures, of sensations, of entire worlds constructed on the basis two very different ideologies, rather requirements, and not against the impracticality of a world ruled by one faith, one science. This aspect came in earlier in this post, too, when I thought I was nitpicking when I surmised Sarewitz's awe upon entering a massive temple was unique: it may have been unique, but only in sensation, not in subject, I realize now.

(Also, I'm sure we have enough of those unknowns scattered around science; that said, Sarewitz seems to suggest that the memorability of his personal experiences in Cambodia are a basis for the foundation of every reader's objective truth. It isn't.)

The author finishes with a mention that he is an atheist. That doesn't give any value to or take away any value from the article. It could have been so were Sarewitz to pit the two worlds against each other, but in his highlighting their unification - their genesis in the human mind, an entity that continues to evade full explicability - he has left much to be desired, much to be yearned for in the form of clarification in the conflict of science with religion. If someday, we were able to fully explain the working and origin of the human mind, and if we find it has a fully scientific basis, then where will that put religion? And vice versa, too.

Until then, science will not give way for religion, nor religion for science, as both seem equipped to explain.

Gunning for the goddamned: ATLAS results explained

Here are some of the photos from the CERN webcast yesterday (July 4, Wednesday), with an adjoining explanation of the data presented in each one and what it signifies.



This first image shows the data accumulated post-analysis of the diphoton decay mode of the Higgs boson. In simpler terms, physicists first put together all the data they had that resulted from previously known processes. This constituted what's called the background. Then, they looked for signs of any particle that seemed to decay into two energetic photons, or gamma rays, in a specific energy window; in this case, 100-160 GeV.

Finally, knowing how the number of events would vary in a scenario without the Higgs boson, a curve was plotted that fit the data perfectly: the number of events at each energy level v. the energy level at which it was tracked. This way, a bump in the curve during measurement would mean there was a particle previously unaccounted for that was causing an excess of diphoton decay events at a particular energy.



This is the plot of the mass of the particle being looked for (x-axis) versus the confidence level with which it has (or has not, depending n how you look at it) been excluded as an event to focus on. The dotted horizontal line, corresponding to 1μ, marks off a 95% exclusion limit: any events registered above the line can be claimed as having been observed with "more than 95% confidence" (colloquial usage).

Toward the top-right corner of the image are some numbers. 7 TeV and 8 TeV are the values of the total energy going into each collision before and after March, 2012, respectively. The beam energy was driven up to increase the incidence of decay events corresponding to Higgs-boson-like particles, which, given the extremely high energy at which they exist, are viciously short-lived. In experiments that were run between March and July, physicists at CERN reported an increase of almost 25-30% of such events.

The two other numbers indicate the particle accelerator's integrated luminosity. In particle physics, luminosity is measured as the number of particles that can pass detected through a unit of area per second. The integrated luminosity is the same value but measured over a period of time. In the case of the LHC, after the collision energy was vamped up, the luminosity, too, had to be increased: from about 4.7 fb-1 to 5.8 fb-1. You'll want to Wiki the unit of area called barn. Some lighthearted physics talk there.



In this plot, the y-axis on the left shows the chances of error, and the corresponding statistical significance on the right. When the chances of an error stand at 1, the results are not statistically significant at all because every observation is an error! But wait a minute, does that make sense? How can all results be errors? Well, when looking for one particular type of event, any event that is not this event is an error.

Thus, as we move toward the ~125 GeV mark, the number of statistically significant results shoot up drastically. Looking closer, we see two results registered just beyond the 5-sigma mark, where the chances of error are 1 in 3.5 million. This means that if the physicists created just those conditions that resulted in this >5σ (five-sigma) observation 3.5 million times, only once will a random fluctuation play impostor.

Also, notice how the differences between each level of statistical significance increases with increasing significance? For chances of errors: 5σ - 4σ > 4σ - 3σ > ... > 1σ - 0σ. This means that the closer physicists get to a discovery, the exponentially more precise they must be!



OK, this is a graph showing the mass-distribution for the four-lepton decay mode, referred to as a channel by those working on the ATLAS and CMS collaborations (because there are separate channels of data-taking for each decay-mode). The plotting parameters are the same as in the first plot in this post except for the scale of the x-axis, which goes all the way from 0 to 250 GeV. Now, between 120 GeV and 130 GeV, there is an excess of events (light blue). Physicists know it is an excess and not at par with expectations because theoretical calculations made after discounting a Higgs-boson-like decay event show that, in that 10 GeV, only around 5.3 events are to be expected, as opposed to the 13 that turned up.

After the Higgs-boson-like particle, what's next?

This article, as written by me, appeared in print in The Hindu on July 5, 2012.

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The ATLAS (A Toroidal LHC Apparatus) collaboration at CERN has announced the sighting of a Higgs boson-like particle in the energy window of 125.3 ± 0.6 GeV. The observation has been made with a statistical significance of 5 sigma. This means the chances of error in their measurements are 1 in 3.5 million, sufficient to claim a discovery and publish papers detailing the efforts in the hunt.

Rolf-Dieter Heuer, Director General of CERN since 2009, said at the special conference called by CERN in Geneva, “It was a global effort, it is a global effort. It is a global success.” He expressed great optimism and concluded the conference saying this was “only the beginning.”

With this result, collaborations at the Large Hadron Collider (LHC), the atom-smashing machine, have vastly improved on their previous announcement on December 13, 2011, where the chance of an error was 1-in-50 for similar sightings.

[caption id="attachment_23590" align="aligncenter" width="600"] A screenshot from the Dec 13, 2011, presentation by Fabiola Gianotti, leader of the ATLAS collaboration, that shows a global statistical significance of 2.3 sigma, which translates to a 1-in-50 chance of the result being erroneous.[/caption]

Another collaboration, called CMS (Compact Muon Solenoid), announced the mass of the Higgs-like particle with a 4.9 sigma result. While insufficient to claim a discovery, it does indicate only a one-in-two-million chance of error.

Joe Incandela, CMS spokesman, added, “We’re reaching into the fabric of the universe at a level we’ve never done before.”

The LHC will continue to run its experiments so that results revealed on Wednesday can be revalidated before it shuts down at the end of the year for maintenance. Even so, by 2013, scientists, such as Dr. Rahul Sinha, a participant of the Belle Collaboration in Japan, are confident that a conclusive result will be out.

“The LHC has the highest beam energy in the world now. The experiment was designed to yield quick results. With its high luminosity, it quickly narrowed down the energy-ranges. I’m sure that by the end of the year, we will have a definite word on the Higgs boson’s properties,” he said.

However, even though the Standard Model, the framework of all fundamental particles and the dominating explanatory model in physics today, predicted the particle’s existence, slight deviations have been observed in terms of the particle’s predicted mass. Even more: zeroing in on the mass of the Higgs-like particle doesn’t mean the model is complete when, in fact, it is far from.

While an answer to the question of mass formation took 50 years to be reached, physicists are yet to understand many phenomena. For instance, why aren’t the four fundamental forces of nature equally strong?

The weak, nuclear, electromagnetic, and gravitational forces were born in the first few moments succeeding the Big Bang 13.75 billion years ago. Of these, the weak force is, for some reason, almost 1 billion, trillion, trillion times stronger than the gravitational force! Called the hierarchy problem, it evades a Standard Model explanation.

In response, many theories were proposed. One, called supersymmetry (SUSY), proposed that all fermions, which are particles with half-integer spin, were paired with a corresponding boson, or particles with integer spin. Particle spin is the term quantum mechanics attributes to the particle’s rotation around an axis.

Technicolor was the second framework. It rejects the Higgs mechanism, a process through which the Higgs boson couples stronger with some particles and weaker with others, making them heavier and lighter, respectively.

Instead, it proposes a new form of interaction with initially-massless fermions. The short-lived particles required to certify this framework are accessible at the LHC. Now, with a Higgs-like particle having been spotted with a significant confidence level, the future of Technicolor seems uncertain.

However, “significant constraints” have been imposed on the validity of these and such theories, labeled New Physics, according to Prof. M.V.N. Murthy of the Institute of Mathematical Sciences (IMS), whose current research focuses on high-energy physics.

Some other important questions include why there is more matter than antimatter in this universe, why fundamental particles manifest in three generations and not more or fewer, and the masses of the weakly-interacting neutrinos. State-of-the-art technology worldwide has helped physicists design experiments to study each of these problems better.

For example, the India-based Neutrino Observatory (INO), under construction in Theni, will house the world’s largest static particle detector to study atmospheric neutrinos. Equipped with its giant iron-calorimeter (ICAL) detector, physicists aim to discover which neutrinos are heavier and which lighter.

The LHC currently operates at the Energy Frontier, with high-energy being the defining constraint on experiments. Two other frontiers, Intensity and Cosmic, are also seeing progress. Project X, a proposed proton accelerator at Fermilab in Chicago, Illinois, will push the boundaries of the Intensity Frontier by trying to look for ultra-rare process. On the Cosmic Frontier, dark matter holds the greatest focus.

Hunt for the Higgs boson: A quick update

And it was good news after all! In an announcement made earlier today at the special conference called by CERN near Geneva, the discovery of a Higgs-boson-like particle was announced by physicists from the ATLAS and CMS collaborations that spearheaded the hunt. I say discovery because the ATLAS team spotted an excess of events near the 125-GeV mark with a statistical significance of 5 sigma. This puts the chances of the observation being a random fluctuation at 1 in 3.5 million, a precision that asserts (almost) certainty.

Fabiola Gianotti announced the preliminary results of the ATLAS detector, as she did in December, while Joe Incandela was her CMS counterpart. The CMS results showed an excess of events around 125 GeV (give or take 0.6 GeV) at 4.9 sigma. While the chances of error in this case are 1 in 2 million, it can't be claimed a discovery. Even so, physicists from both detectors will be presenting their efforts in the hunt as papers in the coming weeks. I'll keep an eye out for their appearance on arXiv, and will post links to them.

After the beam energy in the Large Hadron Collider (LHC) was increased from 3.5 TeV/beam to 4 TeV/beam in March, only so many collisions could be conducted until July. As a result, the sample set available for detailed analysis was lower than could be considered sufficient. This is the reason some stress is placed on saying "boson-like" instead of attributing the observations to the boson itself. Before the end of the year, when the LHC will shut down for routine maintenance, however, scientists expect a definite word on the particle being the Higgs boson itself.

(While we're on the subject: too many crass comments have been posted on the web claiming a religious element in the naming of the particle as the "God particle". To those for whom this monicker makes sense: know that it doesn't. When it was first suggested by a physicist, it stood as the "goddamn particle", which a sensitive publisher corrected to the "God particle").

The mass of the boson-like particle seems to deviate slightly from Standard Model (SM) predictions. This does not mean that SM stands invalidated. In point of fact, SM still holds strong because it has been incredibly successful in being able to predict the existence and properties of a host of other particles. One deviation cannot and will not bring it down. At the same time, it's far from complete, too. What the spotting of a Higgs-boson-like particle in said energy window has done is assure physicists and others worldwide that the predicted mechanism of mass-generation is valid and within the SM ambit.

Last: the CERN announcement was fixed for today not without another reason. The International Conference on High Energy Physics (ICHEP) is scheduled to commence tomorrow in Melbourne. One can definitely expect discussions on the subject of the Higgs mechanism to be held there. Further, other topics also await to be dissected and their futures laid out - in terms vague or concrete. So, the excitement in the scientific community is set to continue until July 11, when ICHEP is scheduled to close.

Be sure to stay updated. These are exciting times!

So, is it going to be good news tomorrow?

As the much-anticipated lead-up to the CERN announcement on Wednesday unfolds, the scientific community is rife with many speculations and few rumours. In spite of this deluge, it may be that we could expect a confirmation of the God particle’s existence in the seminar called by physicists working on the Large Hadron Collider (LHC).

The most prominent indication of good news is that five of the six physicists who theorized the Higgs mechanism in a seminal paper in 1964 have been invited to the meeting. The sixth physicist, Robert Brout, passed away in May 2011. Peter Higgs, the man for whom the mass-giving particle is named, has also agreed to attend.

The other indication is much more subtle but just as effective. Dr. Rahul Sinha, a professor of high-energy physics and a participant in the Japanese Belle collaboration, said, “Hints of the Higgs boson have already been spotted in the energy range in which LHC is looking. If it has to be ruled out, four-times as much statistical data should have been gathered to back it up, but this has not been done.”

The energy window which the LHC has been combing through was based on previous searches for the particle at the detector during 2010 and at the Fermilab’s Tevatron before that. While the CERN-based machine is looking for signs of two-photon decay of the notoriously unstable boson, the American legend looked for signs of the boson’s decay into two bottom quarks.

Last year, on December 13, CERN announced in a press conference that the particle had been glimpsed in the vicinity of 127 GeV (GeV, or giga-electron-volt, is used as a measure of particle energy and, by extension of the mass-energy equivalence, its mass).

However, scientists working on the ATLAS detector, which is heading the search, could establish only a statistical significance of 2.3 sigma then, or a 1-in-50 chance of error. To claim a discovery, a 5-sigma result is required, where the chances of errors are one in 3.5 million.

Scientists, including Dr. Sinha and his colleagues, are hoping for a 4-sigma result announcement on Wednesday. If they get it, the foundation stone will have been set for physicists to explore further into the nature of fundamental particles.

Dr. M.V.N. Murthy, who is currently conducting research in high-energy physics at the Institute of Mathematical Sciences (IMS), said, “Knowing the mass of the Higgs boson is the final step in cementing the Standard Model.” The model is a framework of all the fundamental particles and dictates their behaviour. “Once we know the mass of the particle, we can move on and explore the nature of New Physics. It is just around the corner,” he added.

Good news from the Tevatron

Level: Jedi Master


There's some glad news that's come in today from the Tevatron at Chicago, IL. The analysis of the data it collected last year before shutting down in September shows an excess of events in the mass range of 115-135 GeV/c², with a precision of 2.8 sigma (97.4% CL). This result coincides with the ATLAS and CMS results declared on December 13 last year, providing the broader scientific community and the world the first glimpse of the Higgs boson.

The results were announced at the ongoing Moriond Conference - spanning seven days from March 3 to March 10 - in La Thuile, Italy, which opened with an address by Prof. Francois Englert, one of the contributors who shaped the Higgs mechanism. Ever since the ATLAS/CMS results came out, one important thing as far as the hunt for the Higgs boson is concerned that scientists have learned is the different ways in which the elusive particle can decay. They have used this information to add more readout channels to existing ones at the ATLAS/CMS (two W-boson channels for the former) detectors as well as at the CDF and D-Zero detectors at the Tevatron. Each of these channels will track and monitor one decay channel, or one mode of decay.

Because the Tevatron has shut down, the data it's yielded is more or less final; the only improvisations that can arise will be from refinement of the data. At the same time, apart from the addition of channels, the LHC will also run at a beam intensity of 4 TeV/beam instead of the 3.5 TeV/beam it's been running with in 2010 and 2011. This can be attributed to the encouraging results that have been returned by the experiments hunting for the Higgs boson. The bunch-spacing will remain at 50 nanoseconds.

The constant culpability of the crackpot

The tenet of media operations - in most places - is 'innocent until proven guilty'. The adversarial stance often assumed by television channels and newspaper reports reflect a tendency to view the news from a neutral perspective, to exonerate the common man as much as possible, and to hold ministers and other decision-makers as suspect till a particular threshold. Unfortunately for science, it's exactly the other way around: guilty until proven innocent.

[caption id="attachment_21676" align="aligncenter" width="220" caption="Roger Bacon ('Doctor Mirabilis') was a Franciscan friar (1214-1294) whose emphasis on the scientific method popularized it and made it the experimental method of choice for hundreds of generations of scientists, and continues to be to this day."][/caption]

This is, for many reasons, important. When the media get excited, they often raise the expectations from a particular news story: they ensure that the story is exciting, that it is sufficiently unprecedented so that it challenges existing notions enough to incite interest. And here's where 'guilty until proven innocent' gets to work its magic. Science stories that are capable of becoming exciting have by definition a low chance of being valid. If there was a high chance of the story being valid, it would border on being expected, predictable; covering such an event would be more a chronicling than a witnessing.

By holding a phenomenon guilty, however, nobody would get sucked up in what could be a wild goose chase.

There are a bunch of "discoveries" that, because of their unprecedentedness, purchased interest from the media and allowed the men and women behind the pseudo-discoveries to cash in. One of the greatest examples is the Fleischmann-Pons experiment in cold fusion. When Martin Fleischmann and Stanley Pons of the University of Utah announced that they may have discovered cold fusion on March 23, 1989, there was a flurry of excitement that rippled through military quarters, media offices and the scientific community. According to their paper, there were indications of micro-scale fusion reactions at temperatures of 50 degrees Celsius (as opposed to the millions of degrees they were expected to be at) when deuterium-water was electrolysed in the presence of palladium metal.

[caption id="attachment_21672" align="alignleft" width="199" caption="Martin Fleischmann"][/caption]

The timing couldn't have been better. The 1973 Oil Crisis was fresh in the minds of many people and, seemingly in response to that, cold fusion presented an alternate source of energy that was accessible and more efficient by orders of magnitude. Moreover, just three years earlier in 1986, high-temperature superconductivity had been discovered. When earlier certain materials were thought to be superconducting only at temperatures as low as 4-10 kelvin, a new breed of materials were shown conducting with zero resistance at temperatures as high as 90 and 120 kelvin. Its impact on the discovery of cold fusion was the exculpation of the crackpot: it told the world that having crackpot written all over an experiment didn't mean it couldn't be true.

Fleischmann and Pons were superstars. Soon, a $25-million federal grant was coming the way of U of Utah. However, disturbing developments were being reported from western Europe, other parts of the USA and Japan. The paper Fleishmann and Pons had published in the Journal of Electroanalytical Chemistry did not include the experimental protocol, but that didn't stop scientists worldwide from trying to replicate the research. And they had all been in vain: none of those experiments had detected fusion of any kind at any temperature. In fact, Nathan Lewis, a professor of chemistry at Caltech, set about trying to corroborate cold fusion systematically, trying out all kinds of variations on the process. None of them succeeded.

While the Utah chemists basked in the glory of their finding and the (carefully selected) findings of other groups in America, that also claimed to have observed cold fusion, the death knell was sounded so far afield as CERN: Douglas R. O. Morrison, a physicist, announced that all attempts in western Europe at replicating cold fusion had failed. In order to quell these doubts, Fleischmann and Pons published a "note" in the Journal of Electroanalytical Chemistry in April 1989 that showed a gamma-ray energy peak from their experiment.

Now, it was known at the time that gamma rays released by a fusion reaction could transfer only a certain amount of energy to the detector, which is reflected as a sharp cutoff in the peak after which the energy seems to plummet. The cutoff is called a Compton edge and wasn't observed in the chart in the Journal. When alerted to it, the chemists refused to take any blame, continuously asserting that their experiment was error-proof.

After this incident, interest in the matter rocketed - and negatively. The New York Times published a scathing article on April 30, 1989, titled The Utah Fusion Circus. Its last lines effectively drew the curtains on cold fusion and sent Fleischmann, Pons and the U of Utah back decades in terms of their credibility and accountability.

For Mr. Pons and Mr. Fleischmann, the best bet is to disappear into their laboratory and devise a clearly defined, well-understood experiment that others can reproduce. Until they have that, they have nothing. As for the University of Utah, it may now claim credit for the artificial-heart horror show and the cold-fusion circus, two milestones at least in the history of entertainment, if not of science.

What ultimately made the difference was replicability: when scientists found that the experiment couldn't be replicated, the game was lost. Fleischmann and Pons were held guilty to the end. Their exculpation was all the time hinged on their ability to assert that the experiment would occur anywhere irrespective of geographic location as long as the experimental setup was the same. Because of the nature of their experiment, there was a sizeable measure of urgency to establish priority: as far as anything immensely profitable is concerned, primacy makes all the difference. Woe betide if anyone else claim it first - all would be lost! And in that moment, facts are not checked as rigorously as they should be.

More recently, the same went for the misbehaving neutrinos. When other experiments around the world tried to replicate the phenomenon, nothing happened. In fact, a sister-experiment of OPERA (which first announced the anomaly) called ICARUS drew the curtains more than halfway down within three weeks of the exciting announcement.

[caption id="attachment_21674" align="aligncenter" width="500" caption="The ICARUS experiment at Gran Sasso National Laboratory, Italy"][/caption]

Replication is many things. At the least, it is consensus. At the most, it is a form of characterization that removes a phenomenon out of its germane environment and blesses it with universality, as a result making it explicable within a logical framework and scientific. If the Higgs boson were to be discovered at the Large Hadron Collider in 2012, that will be the first step in a series of experiments on which hundreds of scientists and thousands of engineers will be involved for tens of months. They will check, and then they will check again. If someone somewhere finds that such a boson couldn't be spotted, he won't be snubbed but encouraged to speak up: the closer to the truth you get, the more careful you need to be.

Unfortunately for quacks everywhere, everything about science is the truth.

--

In a curious turn of events, the National Institute of Advanced Studies, India, recommended the Indian government to resuscitate research in cold fusion in 2008. Projects were commenced at IIT Madras, the Indira Gandhi Centre for Atomic Research, and BARC. However, because of persistent scepticism among physicists at chemists, research was halted as of 2011. Find the ToI article here.

The learner as far-seer

I recall a trivial incident from December 13, 2011, which was the day when the ATLAS and CMS experiments at the CERN's Large Hadron Collider (LHC) announced a possible sighting of the Higgs boson particle. It was not so much an incident as something I'm observing now: when the announcement was being made by Fabiola Gianotti, who's in-charge of ATLAS, I had to pause the live-streamed video once every few seconds to look up what she was talking about. A 20-minute-long presentation took more an hour to be understood.

The reason I remember the experience is that, more often than not, one doesn't know when the learning phase of life ends - many, like me, don't even know what comes after it if it ends. However, earlier today, when I was reading a journal article on using laser-induced plasma and the technology's application in particle accelerators, I surprised myself by understanding the entire thing without stopping even once; I could get what the authors were saying even when they were speaking only via formulae.

It was strangely dejecting because one of the most likeable things about particle physics in my opinion is its tendency to throw up previously unknown information just when we least expect it. In fact, even the one thing we thought we knew about this universe - the highest speed possible - was defied last year by some 15,000 neutrinos. And in such a scenario, when the picture suddenly becomes clear, when I can see the jigsaw puzzle board and the different empty shapes here and there waiting to be filled, it's as if I'm ready to start answering the bigger questions and leave the smaller ones behind.

[caption id="attachment_21624" align="aligncenter" width="334" caption="Clinton Davisson (left) and Lester Germer conducted an experiment since named after them - as the Davisson-Germer experiment - in 1927. Six years earlier, Einstein had won the Nobel Prize in physics for his discovery that particles were discrete encapsulations of energy called quanta. In 1927, French physicist Louis de Broglie presented his thesis that all particles have a wave-like characteristic. In the Davisson-Germer experiment, the two Americans stumbled across an electron diffraction pattern where they were expecting an electron diffuse-reflection pattern while studying the surface of nickel.  This proved de Broglie's informed conjecture true."][/caption]

I feel like the depressed man whose psychiatrist suggests he witness a performance by a clown in town. The depressed man then admits he is that clown.

At this point, I see two outcomes. The first one hints that I only want to keep learning and I'm not as interested in "deploying" that knowledge usefully. That is only partly true because, hey, I don't have a particle collider in my backyard that introduces new particles into my life so I can piece the universal puzzle together better. The second outcome suggests that my knowing a lot of things - science-wise and not - is, for the most part, a product of this fear of what-will-or-won't-come-next.

The first outcome doesn't bother me much because I've discovered I like teaching. Even though I may not be using my knowledge of IC engines to fix vehicles on desolate highways, I try and ensure as many people as possible understand how such engines work and do what they want with that knowledge. The same applies for particle physics. However, in this case, the dimension of teaching acquires more weight because its capacity to be misunderstood is great: it's a developing field whose foundations are currently under fire, whose experiments are so complex that multiple governments are helping fund it, whose conclusions are so counter-intuitive that the layman and the physicist are today many perspectives apart.

The second outcome is something I learnt while writing this post. The impetus that holds my two-decade-long learning spree up is nothing but fear, a fear of the unknown. Not learning something on a given day, with me, seems like forgoing a chance to imagine something we might not physically live. It's like the Copenhagen interpretation of quantum mechanics - a.k.a. Schrodinger's cat: for as long as I don't open the box, the cat is both dead and alive, the experience is both there and not there.

Saying "I learn not because I want to" is too bland: I learn because I want to look into the darkest corners of the universe and not see something that I can't understand or gauge in some way.

The popularly perceived notion of beauty comes with inexplicability: the capacity of an entity to defy definition and/or predictability, to defy structure and exhibit a will of its own in form and function. However, the silent reminder we are everyday given that, no matter how far out into the universe we venture or how deep we probe into the atom, the laws of physics are the same is the soul of beauty. And the inexplicability I seek to defy by learning is simply understanding how the same thing that gave us the dung beetle also gave us the Carina Nebula, that the same thing that gave us the Monarch butterfly also have us black holes.

[caption id="attachment_21625" align="aligncenter" width="335" caption="This image of the Carina Nebula is composed of multiple shots taken from the Atacama Desert in South America."][/caption]

I think that's a fear I've enjoyed and enjoy having.

Observing the God particle: An interview with Dr. G. Baskaran (translated from Tamil)

Note: The following telephone interview was broadcast by the BBC on the occasion of CERN’s announcement on December 13. The CERN announced that it had fairly conclusive data that confirmed the glimpsing of a Higgs boson in experiments conducted at the Large Hadron Collider. The interviewee, Dr. G. Baskaran, is a distinguished physicist currently engaged with research at the Perimeter Institute, Canada.

My comments appear in square brackets, [ ], and explain concepts that are required to understand Dr. Baskaran's answers. Statements spoken by the interviewer are marked with bold letters.

The audio of the interview is linked herewith: http://www.bbc.co.uk/emp/worldwide/player.swf

-Begin-

Interviewer: Before we begin a discussion on the Higgs boson, it is important to understand the background of this experiment. Physicists began the search for this particle with the belief that everything in this universe is composed of atoms, and atoms of nuclei. It was due to the contribution of technology that they were then able to break open the nuclei and enter it to find many new particles.

The consequential research has been going on for many years, and led to the formation of a cogent theory that could explain the behavior of all those particles. Physicists called this theory the Standard Model. As they began to work with it, they came across an important glitch: using just those particles that constituted the Standard Model, they couldn’t explain gravitation. Subsequently, physicists directed themselves to find a suitable solution, which took the form of the Higgs boson.

Just like mathematicians, when faced with a problem, use a variable ‘X’ in their equations so they can proceed with their calculations, particle physicists used the Higgs boson as their ‘X’ and proceeded with their unknotting of the universe’s riddles. Since this substitution, which happened in the 1960s, calculations have been going on relatively smoothly but the lack of knowledge of the Higgs’s properties remained elusive.

In this context: on December 13, scientists working at the CERN’s Large Hadron Collider announced that they may have glimpsed the Higgs boson during one of their experiments. When Dr. G. Baskaran, distinguished research chair at the Perimeter Institute in Canada and a Ramanna Fellow with the Institute of Mathematical Science, Chennai, was asked about this announcement, he had this to say: “The things we see in nature, the rocks and sand—as we delve deeper and deeper into them, we come across molecules and atoms. Inside these atoms, we have electrons—orbiting the nucleus—and protons and neutrons inside the nucleus.”

“These elementary particles cannot be seen by the naked eye but only by sophisticated instruments. These particles have been the foundation for a new theory. At such nanoscopic levels of observation, Newton’s laws fail and, instead, quantum theory comes to life. The physics for this theory dates back to almost a century, since the discovery of the electron by Thompson and Einstein’s baptism of photons as the carriers of electromagnetic waves.”

“It was observed that all these particles had mass, and with even more experiments, the values of those masses were found: the particles are very, very light, yes, but they did have a definite mass. So when you consider the mass of the photon, it is zero. The energy for the photon comes from its momentum: it travels at a very high speed. It is impossible to trap or localize a photon, and this has been verified by particle physicists.”

“Avvayyar [a Tamil poet] once spoke about breaking open a sea of particles only to flood seven oceans, and something similar has been happening in the quest for understanding these particles. For example, once physicists broke open the proton, they found quarks and gluons, and when quarks and gluons ‘reacted’, they found neutrinos. The field of physics that concerns itself with the smashing-discovering process is called high-energy physics.”

“Researchers soon realized that they couldn’t experiment with these smaller and smaller particles directly. Instead, they accelerated beams of such particles to high velocities and forced them to collide head-on. At that moment, like how two cars crash into each other and are shot to smithereens, the particles in the beam lose their consistency, break apart, and whatever particles are inside are liberated. Soon, high-energy physics branched out to yield accelerator physics, which deals only with the acceleration of particles to extreme speeds and energies.”

“When particles have an electric charge, placing them close to an electric field will either make the particles move toward or away from the field, in the process accelerating them. According to Albert Einstein, nothing can move faster than light (or photons) and so these particles are accelerated to close to 90-95 per cent the speed of light. When they collided at such speeds, the resulting spew of particles is sieved through to find the building blocks of matter.”

Where and how does the Higgs boson appear in this mesh of theories and particles?

“In the 20^th century, great physicists like Dirac put together the theory of quantum electrodynamics (QED) to understand how particles and forces work together. QED assumes that particles like electrons have mass and that photons don’t. Subsequently, the question QED asks is why electrons have mass and photons don’t, and why so much mass and not some more or some less.”

“In the zoo of elementary particles—about 50 of them were assumed to exist by the time QED was formulated—a pattern was beginning to emerge when physicists attempted to answer the question. The pattern would eventually become the Standard Model, and in the meantime, physicists Abdus Salam, Steven Weinberg and Sheldon Glashow were awarded the Nobel Prize for their efforts in working the Model out. I knew Prof. Salam personally; now he is no more.”

“The trio’s principle contribution was a framework within which theories could be analyzed to determine how mass is generated. This framework worked with what are now called the Higgs field, the Higgs mechanism and the gauge bosons. The significance of their theory was that all those particles that were hypothesized by them were eventually observed in experimental setups. Everything but the Higgs boson.”

In all mathematical calculations up to this point, most predictions have been hinged on the possible existence of the Higgs boson. Therefore, it became important to look for this particularly.

“While the theory was successful, the significance of ‘sighting’ the particle kept growing. The boson—a moniker named for Satyendra Nath Bose—worked its magic in unseen ways, and that was frustrating. Now, the elementary particles are classified as bosons and fermions. Electrons, protons and neutrons are all fermions, and photons are bosons. The Higgs boson is what is called a scalar boson.”

[All particles have a property called spin that is one of the definers of their state in quantum physics. Fermions have fractional spin, like ½. Bosons, on the other hand, have integer spin, like 1 or 0. Any boson termed scalar will have a spin of 0.]

“Research in physics has revealed that the Higgs boson exists in a ‘rain of energy’, i.e. its energy is in the range of a hundred giga-electron volt (GeV). Once they set about combing for appearances of the Higgs boson in reactions that happened at such an energy level, however, they couldn’t find anything of relevance. In furtherance of this search, the Large Hadron Collider (LHC) was set up at the CERN in Europe. In an experiment conducted in this ultra-precise high-energy accelerator, scientists have claimed today that they have glimpsed the Higgs boson.”

“There is a fascinating correlation between the search for the Higgs boson and the question of why particles have mass, which was brought out by a physicist named Yoichiro Nambu who won the Nobel Prize in physics for it [in 2008]. Nambu’s theory explained the origin of mass using the phenomenon of BCS-superconductivity.”

[Named for John Bardeen, Leon Anderson Cooper and John Robert Schrieffer, the BCS theory explains that superconductivity is the result of electrons, in extremely cold temperatures, condensing into boson-like pairs, called Cooper pairs that cannot be “kicked” by the ambient temperature to resist the flow of electric current.]

“Nambu was inspired by Cooper’s idea of pairing to suggest that the two mechanisms—pair-generation and mass-generation—were similar. This is the beautiful thing about physics: two seemingly unrelated phenomena observed in fields conceptually far-apart will find kinship simply because physics is unbiased and unifying. Anyway, this similarity between the two mechanisms provides an alternate name for the Higgs boson: the Anderson-Higgs boson. Dr. [Phil] Anderson is a renowned man in physics, who currently works at Princeton university, and I have been collaborating with him since 1984.”

What will physics look like if the truth of the Higgs boson is cemented?

“In my opinion, it will only complete a chapter in the history of elementary particle physics and reopen the next chapter for study. Elementary particle physics requires many other theories to become fully explicable like, for instance, supersymmetry. According to supersymmetry—which Abdus Salam was also involved in—every fermion ought to have a boson counterpart. This means that the electron should have a corresponding electronic boson. However, such bosons are yet to be spotted. Their significance arises out of the possibility that such counterpart-bosons could be responsible for determining which particle has how much mass.”

“At the cutting edge of physics research, at which the LHC lies, one of the goals is to find these supersymmetric partners. Another is to find dimensions other than the four we engage with [length, breadth, depth and time]. Some physicists argue that there multi-dimensional systems of the order of 22 dimensions, whose signatures might pop up during experiments at the LHC.”

At the same time, the CERN announcement only claims a possibility of the Higgs boson’s existence, not a certainty. They also haven’t announced what conditions or phenomena will establish such a certainty. Why do you think this is so?

“The Higgs boson is extremely short-lived, i.e. the particle decays before instruments in the detectors can focus on it and record its properties. For example, an electron might escape detection by speeding away, sometimes it might decay under higher energies to smaller particles, but the electron will have remained an electron until the moment it ‘dies’, either by decaying or annihilating in the presence of a positron to yield a gamma ray.”

“An electron’s lifetime is very, very long. The lifetime of a Higgs boson, on the other hand, is very, very low. Therefore, the way to detect a Higgs boson is to look for the presence of its decay signature. A lot of errors can creep into the process of looking for this signature. This is why physicists, who are reluctant to commit that they’ve eliminated all errors, are also reluctant to claim that they’ve found the Higgs boson for sure.”

Interviewer: Dr. G. Baskaran, senior professor, Institute of Mathematical Science, Chennai

-End-

So where does the Higgs boson come from?

(Before we begin: all uses of the term "vacuum" in this discussion do not denote the absolute nothingness we know it colloquially to be. In quantum field theory, a vacuum is a space that contains "fleeting electromagnetic waves, within which things pop in and out of existence.")

[caption id="attachment_23450" align="alignright" width="300"] "Noob! I am your father!"[/caption]

When Alderaan was annihilated by the Death Star, Obi-Wan Kenobi sensed it even though he was not in the vicinity of the Empire's fleet. He said, "I feel a great disturbance in the Force, as if millions of voices suddenly cried out in terror, and were suddenly silenced." Now, imagine a place of absolute nothingness, also called a zero-point field, within such a Force, that contains no physical particles or energy quantizations. The best way to characterize this system would be in terms of its symmetry: that, in any direction starting from the centre of this vacuum, the probability of an event occurring is equal and zero. Now, imagine sticking your finger into such a system.

The first thing that happens is the symmetry breaks. A mass excitation is said to have been introduced in the zero-point field and that, starting from the centre and moving in any direction, the chances of finding a finger in one particular direction are going to be very good. Therefore, in anticipation of the finger being introduced into the system, the equations that define the system in the beginning must be able to account for symmetry-breaking. Now, eliminate any fingers and imagine that instead of a zero-point field, there is a continuous sea of particles with an unbroken energy symmetry, i.e., the chances of finding a perturbation in any direction is zero and that there is no mass excitation in the spectrum of possible excitations.

[caption id="attachment_23452" align="aligncenter" width="305"] A radial probability-cloud showing the probability decreasing from 1 (at the centre) to 0 (moving outward)[/caption]

While the system is in this phase, instantaneously expose it to an extremely high-temperature surrounding (t→10¹⁵ K, or approaching a thousand-trillion degrees Celsius). The sea of particles begins to vibrate because of the excess energy that has been imparted to their system, but the symmetry isn't yet broken. Suddenly, at 10¹⁵ K, the symmetry breaks spontaneously—which is thermodynamic lingo for "irreversibly"—but there is still no mass excitation.

That is because of Goldstone's theorem, formulated by Jeffrey Goldstone, which states that spontaneous symmetry breaking will occur only with massless excitations. The loss of symmetry can be interpreted as a gain of perturbations, as if a long-wavelength wave has been introduced as a disturbance into the system, giving rise to a field that acquires a non-invariant expectation value, and not necessarily corresponding to a vacuum expectation.

[caption id="attachment_23453" align="aligncenter" width="600"] Illustration of a standing wave, with amplitude described along the y-axis and its frequency, along the x-axis[/caption]

Simply put, the sea of particles can be thought of as a quantum fluid, or an infinite fabric. Beyond the critical temperature, the energy excitations of the particles pushes them to fall out of order, like a group of prisoners in a prison where the conditions are steadily getting worse: there will be a riot at some point, and the condition that precipitates the riot will have induced criticality in the system of prisoners. Just like the universe started to cool a few fractions-of-a-second after the Big Bang, a rollback of the adverse conditions will induce a gradual return to normalcy in the prison—a long-wavelength, low-frequency return to square one. At the same time, the guards remain on alert for small and localized disruptions because there is a non-zero expectation value (of an event).

[caption id="attachment_23454" align="aligncenter" width="640"] A history of the Big Bang: after one-hundred-billionth of a second, the symmetry has been broken to differentiate the electromagnetic and weak forces at an energy of 1 Tev. The LHC has been recreating just this situation by smashing together two beams of protons, each of 3.5 TeV, to reunify them as the electroweak force and look for the Higgs boson.[/caption]

For order to have resulted after the symmetry is broken, an order parameter is introduced. This is because, when the system was symmetric, the uniform probability eliminated the need to characterize any variations simply because the variations weren't there. After the spontaneous symmetry breaking, the system is said to be ordered in terms of the order parameter, although this is a different kind of order: one where subsystems can interact with excitations in the background field—the Force—to give rise to frames of reference (FoR). FoRs are localizations of activity that are logical enough to become something against which other such activities can be compared. (Notice now that the variations of the order parameter in the system are symmetric.)

The gain of perturbations in the system is understood in terms of the exchange of massless particles called the Nambu-Goldstone bosons, whose existence was postulated by Goldstone and Yoichiro Nambu, and the system is said to be in the Nambu-Goldstone mode. Such bosons arise out of the perturbing energy of the surrounding heat-reservoir to mediate the perturbing force. At the same time, the symmetry-breaking should've resulted in the formation of two "pieces" from one. These are two of the four fundamental forces of nature: the electromagnetic force and the weak force, the latter being responsible for radioactivity and beta decay. They are forces that are long-term manifestations of energy-transfer.

(The other two fundamental forces are gravitation and the strong nuclear force. Gravitational forces are mediated by the Higgs boson, whose origins we're exploring, and the strong force is mediated by gluons, which bind to quarks, other gluons and anti-gluons. The strong force holds the protons and neutrons in a nucleus together.)

[caption id="attachment_23455" align="aligncenter" width="275"] Jeffrey Goldstone and Yoichiro Nambu[/caption]

Just like the Nambu-Goldstone bosons are carriers of the perturbing force, two other kinds of bosons are brought into existence to carry the electromagnetic and weak forces: these are the massless photons (for the Em force) and the initially-massless W^±/Z bosons (for the weak force). The debut of massiveness, or the possession of mass, happens when the W^± and Z bosons "eat" the Nambu-Goldstone bosons and become extremely massive, in the process largely reducing the range of the weak force (hence, the name). The mass they acquire is of the non-vanishing sort, which means they can't lose it: the consumption is permanent. The process as a whole is known as the Higgs mechanism, and here we finally come to the Higgs boson, or the God particle.

Just as the original Nambu-Goldstone bosons arose out of an interaction between the high temperature and the background vacuum—again, the Force—so did the W^± and Z bosons arise out of the interaction between the Nambu-Goldstone bosons and what is called the Higgs field: a quantum field that pervades the entire universe and could be imagined to be the Force itself. Mathematically, the Higgs field has four components, two neutral and two charged just like an electric field has two components, its strength at a point and its direction at that point. The four Higgs components are all Nambu-Goldstone bosons: the two charged ones are consumed by the W⁺ and W^- bosons and one of the neutral ones is consumed by a Z boson. The remaining neutral boson had to have been consumed by a fourth boson or the quantum field would've exhibited a disturbance quite unlike what we've ever experienced.

This fourth boson is the Higgs boson—which means the fourth fundamental force is the gravitational force. The particle's existence means the presence of a Higgs field, and the presence of a Higgs field means the consumption by W^± and Z bosons of the Nambu-Goldstone bosons, and the consumption means the occurrence of a Higgs mechanism. Ultimately, the occurrence of a Higgs mechanism means its present formulation, along with that of the electroweak symmetry, holds true, firmly attesting to the Standard Model's ability to explain the dynamics of all the known subatomic particles.

[caption id="attachment_23456" align="aligncenter" width="640"] A schematic view of the LHC[/caption]

Wikibook: Understanding mass in the framework of quantum gravity

Understanding the Higgs mechanism is one thing, but understanding the concept of mass in the framework of the general theory of relativity and quantum gravity is quite another. Many of the books on the subject are priced unaffordably in India and so I compiled a Wikibook with the assistance of the Book Creator on Wikipedia.

Here is the link for it. The chapters deal with loop quantum gravity (because it attempts to reconcile the approaches of quantum mechanics and general relativity), quantum field theory (because it deals with quantum mechanical models of many-body systems), general relativity, manifold spaces (because its study serves as a valuable precursor to understanding QFT) and quantum chromodynamics (because it serves as an alternate approach to understanding gravity by studying fluxes).

Wikipedia rocks.

With the quarry cornered, the real hunt for the Higgs boson begins!

The CERN has announced that the Higgs boson, a.k.a. the God particle, has been glimpsed with a mass in the vicinity of 126 GeV and with a general restriction between 115.5 GeV and 131 GeV (95% confidence level, or CL) with a 3.6-sigma local precision and a 2.3-sigma global precision at a luminosity of 4.9 inverse-femtobarn (fb^-1) by the ATLAS experiment.

In other words, there does exist a good chance of a quarry, and the quarry has been cornered.

[caption id="attachment_20965" align="aligncenter" width="530" caption="From the presentation by ATLAS's Fabiola Gianotti (unfortunate that she had to use Comic Sans)"][/caption]

This means physicists know that the mass of the Higgs boson is not in the high-mass region (above 200 GeV) but in the low-mass region (<200 GeV). Consequently, the channels that are tracking events in this region will be watched specifically and more carefully in the checks that will be run in 2012. The checks are necessary because the events will now have to be studied with greater luminosity (measured by the inverse-femtobarn) and because the standard deviation of the errors will have to be brought down from 0.54011 GeV/c² (2.3-sigma) precision to 0.00023 GeV/c² (5-sigma).

[caption id="attachment_20968" align="aligncenter" width="530" caption="The yellow box shows what will change during the 2012 checks"][/caption]

In order to detect the Higgs boson in the vicinity of 125 GeV to 126 GeV at the 5-sigma tolerance level, the luminosity will have to be increased from what is now 4.9 fb^-1 to 20 fb^-1. Also, the low-mass observation channels will each have to have a precision high enough to keep deviations below 0.400138 GeV/c². The Compact Muon Solenoid (CMS) experiment has also done a good job of excluding energy levels in between 127 GeV and 600 GeV with a 95% CL, and from between 117 GeV to 543 GeV with a 99% CL.

[caption id="attachment_20970" align="aligncenter" width="530" caption="The exclusion limits arrived at by the CMS experiment"][/caption]

[caption id="attachment_20969" align="aligncenter" width="530" caption="The center chart shows the broad excess just above the mean-mark, a flat plateau that points at an event "somewhere there", and the chart on the right, corresponding to a high-sensitivity detection channel, shows a sharp peak (toward the left) - a finer image of the plateau."][/caption]

The final results and papers will be published by the end of January, together with an update on the installation of new channels and refined analyses. The high-points of the entire experiment were the 95% CL exclusion of the 127-600 GeV range and the observation of a small excess of events in the 115-127 GeV mass range with a (high) deviation of 0.62009 GeV/c². Because of the low precision, the observation could also have been a result of background fluctuations in the experiments, necessitating a verification in 2012 - which will yield a definite answer.

Sailing the intergalactic pea soup

It's really hard for many people to get excited about the impending announcement by CERN concerning the search for the Higgs boson (or the 'God' particle). The only reason I'm following it is because I'm interested in nuclear physics and the prospect of having the Higgs mechanism validated excites me. While I believe that any more-conclusive words on the subject will have a great impact on the future of science and scientific research, my colleagues in journalism think it is just another event, a yet-another-small-discovery that further cements our understanding of the universe.

[caption id="attachment_20955" align="aligncenter" width="530" caption="The ATLAS (A Toroidal LHC ApparatuS), above, and the CMS (Compact Muon Solenoid) are two general-purpose detectors on the Large Hadron collider. They gathered the hundreds of thousands of gigabytes of data that scientists are sifting through looking for signs of the Higgs boson."][/caption]

 

[caption id="attachment_20956" align="aligncenter" width="483" caption="The Compact Muon Solenoid (CMS)"][/caption]

At the same time, political and sports stories find purchase just about as soon as they transpire and from almost all quarters they reach to. That science lacks the same hold has been the subject of many a technical discourse in the past. Even more: given how we're in the golden age of science journalism, many of today's stories, if not all, do a much better job of making people understand why and how science is important irrespective of their academic backgrounds. But even now, our progress is slow and difficult. In this context, as we enter an era of physics even more elegant in its complexity, an era of science as such that finally thinks itself in a position to explain everything that it encounters, journalists have an opportunity.

Windows such as this don't open often because the windows that do don't have the sort of significance and import that will get them on the front-page, that will secure them the modicum of attention required to sustain enough attention in the matter to draw questions and more interest from readers.

When Albert Einstein formulated the general and special theories of relativity, it was the beginning of a fascinating time for physics and chemistry: finally, something had been put in place that was robust and did not succumb to any probing thought experiment it was subjected to. Even though it pushed what it couldn't explain to the fringes of phenomenology, it was just as good because it consistently explained everything that we had observed and could observe - all the way from the smallest particles to the largest stars. Also the discoverer of the photoelectric effect that eventually lead to the packaging of the Standard Model, Einstein provided invaluable focus to a subject many until then couldn't comfortably approach.

[caption id="attachment_20957" align="aligncenter" width="436" caption="Particles postulated by the Standard Model of particle physics"][/caption]

In other words, tomorrow's announcement will reveal the picture that Einstein and his successors jotted out the dots for. A definite "Yes" will seal the deal for particle physicists and provide them with the foundation necessary to explore the nature of dark matter and the origins of the universe. A definite "No" will send them scurrying back to their notes and prompt a critical scrutiny of what went wrong and how it can be fixed.

I believe that there can be not many other moments that will possess the same significance as the propsect of finding the Higgs boson presents. In fact, even its invalidation will be just as good because it will debunk the simple Higgs mechanism and force reconsideration.

[caption id="attachment_20958" align="alignleft" width="240" caption="The Higgs mechanism"][/caption]

Simply, the Higgs boson is the protagonist in the play of particles that imparts mass to everything in this universe. To understand the mechanism with which it imparts mass, there is the oft-quoted example of a famous movie star walking into a crowded room. As he enters through the door, he gathers a group around him that slows him down in his journey through the room. The group moves with him: those he leaves behind melt away while those he moves toward come forward. Finally, when he exits the room, the group disappears, too, and the room is just crowded once more. Similarly, the Higgs boson creates a charged field around it. When particles move through this field, they acquire some mass that slows them down accordingly.

There are only a few unexplained "mysteries" in the realm of physics. The more famous amongst them are the source of gravitational forces - accounted for by the hypothetical Higgs mechanism - and the nature of dark matter. The 2011 Nobel Prize for physics was awarded to Saul Perlmutter, an astrophysicist who proved that galaxies are moving farther apart not at decelerating or constant speeds but at increasing rates. This means that after the initial blow of the Big Bang, something is pushing the galaxies farther faster, and this something has been hypothesized to be dark matter.

[caption id="attachment_20960" align="aligncenter" width="475" caption="The frontiers of physics"][/caption]

Reporting such stories is going to be different from reporting other stories because this is a frontier of physics, where it is easy to trip and fall, difficult to pick oneself back up and where almost nothing is certain. At the cutting edge, the byword has to be caution more than anything else, including interest and adventure, because of two reasons.

1. Physics at the cutting-edge is inaccessible to almost everyone who's not at CERN or some other high-tech lab. In such a case, misrepresentation is misguidance magnified by the unfortunate inaccessibility.


2. The farther we move into uncharted territories, into the "intergalactic atomic pea soup" as it were, the more we're assuming holds true. Think of this as a sailor who has lost his way in the sea but providentially happens to have tied his boat to a safe harbour by means of a very long rope. As he moves farther away from that harbour, the more rope he will spend in between, and more is the rope he will have to account for that has not been cut.

An interview of physicist and recent author Lisa Randall by The New York Times illustrates this seldom exercised caution in such matters by many journalists reporting the issue.

Q. What do we know about it so far?

A. Experimenters have already ruled out a large range of masses. The Higgs boson, if it exists, has to be heavier than 114.4 giga-electron volts (GeV), which are the units of mass that particle physicists use. By comparison, protons, the bedrock of ordinary matter, are about 1 giga-electron volt, and an electron is only half a million electron volts.

Based on recent searches by the L.H.C., the Higgs boson is also excluded between about 140 GeV and 500 GeV. This makes the most likely region for the Higgs mass to be between about 115 and 140 GeV, which is the range Tuesday’s results should focus on, although in principle heavier Higgs boson masses are in contention too.

I don’t want to shatter hopes, but don’t count on Tuesday’s results being definitive. This is the toughest range of masses for the L.H.C., and detection is tricky for this range. I suspect they will have enough evidence not to exclude the Higgs, but too little to fully pin it down without next year’s data.

Because of its notoriously elusive nature, the search for the Higgs boson has acquired an anthemic proportion which makes it easier for the story to be reported when the more arduous aspects of it are filtered out. It makes journalistic capitalization more accessible, which will push the twin notions of ethical science reporting and essential science reporting further apart. And where ethical science reporting accounts for the trust between the writer and the reader, essential science reporting accounts for what stories are important and therefore must be covered.

[caption id="attachment_20961" align="aligncenter" width="520" caption="Using "Don't you know who I am!" to define right and wrong where they haven't been defined can a dangerous thing."][/caption]

Breaking a science story just because it happened somewhere and presents news-like information to a local group is not the duty of a journalist. The duty is to inform his/her readers which piece of news is more important and why. Unlike other subjects that are reported, science journalists don't have the liberty of drawing from a repetitive history to forecast the future. They can never possess the intellectual resources necessary to influence readers to repeat the past. In taking anyone forward, science journalists must guide with both the direction of each step and the distance it covers.

When the time does come for the revelation that it won't be another year before the verifications are all complete, many people will have lost interest in the subject because what they thought would've mattered to them would've happened a year ago. Instead of creating false reasons to celebrate the findings just because nobody is noticing, reporters must undertake a sustained coverage of important issues. If they don't - if we don't - then it's going to become very hard to get readers to catch up with what's going on.

[caption id="attachment_20962" align="aligncenter" width="530" caption="Context is important: it sets the tone of the story as well as determines where we're headed to."][/caption]

As the search for the Higgs boson nears an important milestone, the interactive forces within the field highlight the importance of focusing stories on the ancillary qualities of the scientific method instead of the phenomena born thereof. For those for whom scientific principles don't mean much, for those whose readership I, the journalist, require and need to cultivate, stories with misconstructed contexts will work against my intention to bridge the gap between research and technology. Like the following anonymous quote implies,

The eye cannot see what the mind does not know

Not telling the reader something he doesn't know exists can be used both to preserve a narrow context where it may be necessary to keep away confusion and to secure personal interests and not risk public interference in the matter. The former is difficult to use, the latter is just wrong. We must carefully introduce, sustain and finish as does science: with "systematic observation, measurement, and experiment, and the formulation, testing and the modification of hypotheses."