Signs of a slowdown

The way ahead for particle physics seems dully lit after CERN's fourth-of-July firecracker. The Higgs announcement got everyone in the physics community excited - and spurred a frenzied submission of pre-prints all rushing to explain the particle's properties. However, that excitement quickly died out after ICHEP '12 was presented with nothing significant, even with anything a fraction as significant as the ATLAS/CMS results.

[caption id="attachment_23677" align="aligncenter" width="600"] (L-R) Gianotti, Heuer & Incandela[/caption]

Even so, I suppose we must wait at least another 3 months before a a conclusive Higgs-centric theory emerges that completely integrates the Higgs mechanism with the extant Standard Model.

The spotting of the elusive boson - or an impostor - closes a decades-old chapter in particle physics, but does almost nothing in pointing the way ahead apart from verifying the process of mass-formation. Even theoretically, the presence of SM quadratic divergences in the mass of the Higgs boson prove a resilient barrier to correct. How the Higgs field will be used as a tool in detecting other particles and the properties of other entities is altogether unclear.

The tricky part lies in working out the intricacies of the hypotheses that promise to point the way ahead. The most dominant amongst them is supersymmetry (SUSY). In fact, hints of existence of supersymmetric partners were recorded when the LHCb detector at the LHC spotted evidence of CP-violation in muon-decay events (the latter at 3.9σ). At the same time, the physicists I'm in touch with at IMS point out that rigid restrictions have been instituted on the discovery of sfermions and bosinos.

The energies at which these partners could be found are beyond those achievable by the LHC, let alone the luminosity. More, any favourable-looking ATLAS/CMS SUSY-results - which are simply interpretations of strange events - are definitely applicable only in narrow and very special scenarios. Such a condition is inadmissible when we're actually in the hunt for frameworks that could explain grander phenomena. Like the link itself says,

"The searches leave little room for SUSY inside the reach of the existing data."

Despite this bleak outlook, there is still a possibility that SUSY may stand verified in the future. Right now: "Could SUSY be masked behind general gauge mediation, R-parity violation or gauge-mediated SUSY-breaking" is the question (gauge-mediated SUSY-breaking (GMSB) is when some hidden sector breaks SUSY and communicates the products to the SM via messenger fields). Also, ZEUS/DESY results (generated by e-p DIS studies) are currently being interpreted.

However, everyone knows that between now and a future that contains a verified-SUSY, hundreds of financial appeals stand in the way. :D This is a typical time of slowdown - a time we must use for open-minded hypothesizing, discussion, careful verification, and, importantly, honest correction.

A dilemma of the auto-didact

If publishers could never imagine that there are people who could teach themselves particle physics, why conceive cheaper preliminary textbooks and ridiculously expensive advanced textbooks? Learning vector physics for classical mechanics costs Rs. 245 while progressing then to analytical mechanics involves an incurrence of Rs. 4,520. Does the cost barrier exist because the knowledge is more specialized? If this is the case, then such books should have become cheaper over time. They have not: Analytical Mechanics, which a good friend recommended, has stayed in the vicinity of $75 for the last three years (now, it's $78.67 for the original paperback and $43 for a used one). This is just a handy example. There are a host of textbooks that detail concepts in advanced physics and cost a fortune: all you have to do is look for those that contain "hadron", "accelerator", "QCD", etc., in their titles.

Getting to a place in time where a student is capable of understanding these subjects is cheap. In other words, the cost of aspirations is low while the price of execution is prohibitive.

Sure, alternatives exist, such as libraries and university archives. However, that misses the point: it seems the costs of the books are higher to prevent their ubiquitous consumption. No other reason seems evident, although I am loth to reach this conclusion. If you, the publisher, want me to read such books only in universities, then you are effectively requiring me to either abstain from reading these books irrespective of my interests if my professional interests reside elsewhere or depend on universities and university-publisher relationships for my progress in advanced physics, not myself. The resulting gap between the layman and the specialist eventually evades spanning, leading to ridiculous results such as not understanding the "God" in "God particle" to questioning the necessity of the LHC without quite understanding what it does and how that helps mankind.

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.

Understanding accelerator luminosity

Advanced physics is essentially a study in precision, and the particle accelerators of today that are located at the cutting-edge Intensity and Energy Frontiers work against approximations everyday. The particles they synthesize, track and study are so small, quick and short-lived that they might as well have simply popped in and out of existence and nothing would've changed. However, fortunately, that's not the point of studying these things at all: understanding why the "popping" happens at all is what is key.

[caption id="attachment_21639" align="aligncenter" width="346" caption="Some famous accelerators: (clockwise from top-left) Kō Enerugī Kasokuki Kenkyū Kikō (KEK), Japan; Tevatron at FERMILAB; CERN's Large Hadron Collider; and LINAC at Stanford Linear Accelerator Centre."][/caption]

At the world's most powerful collider, the LHC at CERN, two proton beams are shot around 27-km long rings. These are not continuous beams but ones intermittently segregated into bunches, like a pulse. Each of these bunches contains 2,808 protons (which are the hadrons in question) and there are 1,000 bunches per beam. It is ensured that the bunches from the rings don't cross each other - "collide" - more than once every 25 nanoseconds. At this rate, 112.32 billion protons - 56.16 billion from each side - meet each other every second. This is what every particle accelerator makes possible: a rendezvous.

Once this is done, the detectors take over, and they are the real measure of an accelerator's performance. The accelerator will have ensured that enough collisions occur so that the detector can record at least one (even though I'm understating the ratio, it is really quite small). Ergo, to measure a detector's performance as either being good or bad, or perhaps even as somewhere in between in the rare case, how much it is capable of seeing is what makes the difference. This is where luminosity comes in.

The generic definition of luminosity is that it is a measure of the quantity of light that passes through an area each second, and so its units are per metre-squared per second. Accelerator physics adopted this definition and modified it a little: accelerator luminosity is a measure of the number of particles that pass through a given area each second multiplied by the opacity of the detector. This final parameter is necessary because it also accounts for the tendency of some particles to escape detection by passing right through the target: if the target's opacity is high, most particles will be "seen", and if it is low, most particles will be invisible to the cameras' eyes.

(Even though the definition of luminosity indicates the number of particles that pass through an area per second, its meaning in the confines of an accelerator changes: it is the number particles that are seen by a detector irrespective of how many particles there are in total.)

Inside the accelerator and in the presence of the detector, the following differential equation dictates the machine's luminosity:



Here, σ is the total cross section of the detector - the area that is exposed to and receives the stream of particles, N the number of particles, L the instantaneous luminosity, and t the duration over which the detector remains in operation. The opacity affects σ. (The 'd' denotes that the value of the parameter is being considered for an infinitesimal period of time, as indicated by the dt in the denominator. If it was dx or dy instead of dt, it would mean the value of N is being considered over a very small distance in the x or y direction.)

If Ω (omega) were the solid angle through which the detector's cross section was exposed, its differential cross section is computed as



 

This formula gives the luminosity with respect to the angular cross section (as opposed to a planar surface) as the number of particles per degree per second, and from here, the number of particles per volume of space can be easily computed. The formula also shows that the greater the detecting cross section per degree of solid angle, the greater the luminosity per degree of the same angle (or, "particle-seeability"). And for the detector to be useful at all, the instantaneous luminosity has to be high enough to detect particles so small that... well, they're incredibly small. Therefore, the smaller the particle being studied, the larger the detector will be.

There is no better way to illustrate this conclusion than to point, again, to the LHC, where the Higgs boson particle, one of the smallest particles conceivable, a veritable building block of nature, is being hunted by the world's largest detector (which also has a misleading name): the Compact Muon Solenoid (CMS). The CMS, weighing 12,500 tons, has been able to achieve an astounding integrated (as in not instantaneous) luminosity of 1 per femtobarn: 1 barn is one-hundred-billion-billion-billionth of a squared metre; 1 femtobarn is one-million-billionth of that!

[caption id="attachment_21633" align="aligncenter" width="461" caption="The total integrated luminosity delivered to and collected by CMS until 17th June, 2011."][/caption]

Another detector at the site, the much more prolific A Toroidal LHC Apparatus (ATLAS) weighs 7,000 tons and has a luminosity of 50 per femtobarn. The under-construction iron-calorimeter (ICAL) detector at the India-based Neutrino Observatory (INO) in Theni, Tamil Nadu, will weigh 50,000 tons after being completed in 2015 and will be used to track and study neutrinos exclusively. Neutrinos are particles more elusive than the Higgs, and, though the luminosity of ICAL hasn't been disclosed, we can expect the device to be one of the pioneers in detector technology simply because its luminosity must be that low for the project to be a success.

This much and more can be said of accelerator luminosity. While the media goes gaga over the energies at which the beams are being accelerated, there is a silent revolution in detector technology happening in the background, a revolution that is spawning brilliant techniques to spot the fastest, smallest and most volatile particles. These detectors also consume the greater part of accelerator budgets to build and the greater part of total maintenance time. Some of the most advanced detectors in existence include hadronic calorimeters (HCAL), ring-imaging Cherenkov detectors (RICH detectors) and muon spectrometers.

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.

χb (3P) discovered at the ATLAS

The ATLAS detector at the CERN confirmed the existence of another particle predicted by the Standard Model, this one much less prolific than its apotheosized cousin, the Higgs boson, on December 22. It's the Upsilon meson, which is a coupled state of the bottom quark and the bottom antiquark. Such a coupling makes the meson a quarkonium, and so it also assumes the name of bottomonium.

Such a flavourless meson, also called a χ (chi) particle, exists at various excited states, or excitation modes, just like a hydrogen atom, and it decays to each state by the radiation of a photon (γ). The Upsilon meson was first observed in 1977 in an experiment headed by Leon Lederman at the Fermilab, Chicago, with a mass of 9.46 GeV/c². The ATLAS discovery corresponds to a higher excitation state, χ_b (3P), wherein the particle's mass is 10.539 ± 0.004 GeV/c².

[caption id="attachment_21088" align="aligncenter" width="600" caption="The spike in activity corresponds to a detection. The Upsilon meson was observed in three independent channels."][/caption]

Like the electronic orbitals in an atom, each decay state is designated as belonging to an S, P or D energy-state, and the discovery is that of a χ_b (3P): a flavourless meson at the 3P excitation mode. In the second diagram, the particle shows up as the right-most peak on the purple (lowermost) curve, corresponding to ~10.5 GeV on the x-axis. It hasn't shown up in earlier experiments because only the Large Hadron Collider has been able to supply the high rate of collisions required to record the particle's existence before it decays in 1.21×10⁻²⁰ seconds (at 9.46 GeV/c²).

The corresponding pre-print paper submitted by the ATLAS Collaboration is available here.

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-

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."

Clear and present danger

“Revolutions in information and communication technologies have always been based on small findings in solid state physics” quips Dr. G. Baskaran, firmly establishing both the place and scope of technology. Affiliated with the Perimeter Institute in Waterloo, Canada, Dr. Baskaran is a renowned theoretical physicist. He recently delivered a short lecture at the Asian College of Journalism, speaking on everything from the role of science and the ongoing battle to explain super-luminary neutrinos to the future of science.

His statement couldn’t have come at a better time to remind the world of the necessity of science – and its techniques that we call technology. In the face of looming budget cuts in the USA and Europe, politicians and policy-makers have been raising serious questions about the necessity of everything from privately-owned small research labs to proposed upgrades to the Large Hadron Collider (LHC) at CERN.

The evolution of science and technology has been associated with greater unity amongst peoples, Dr. Baskaran said, and better health, wealth, education and opportunities to preserve our culture. “There is some responsibility also”, he adds with a confidence mature with experience.

With likely the greatest ICT revolution at its peak, his words suggest that the technology fuelling it is also maturing in the sense of its acceptance and social penetration. Perhaps it is time for the world to get on the wagon, increase its investments in R&D, and start saving up. The future it seems can stand only to gain because historical ties are snapping in the face of a rupture that is allowing previously-lagging nations like India and China give past-leader USA a run for its money. Increased capitalist traction in the form of tablet computers and smartphones should be thanked for this.

Perhaps the best example of such an opportunity is the increasing feasibility of multi-state-owned research laboratories. The pioneer in this regard is CERN, which was funded and built by 12 countries in 1954, a number that has increased to 20 since, and currently receives funding from 69 countries worldwide. Next in line are the soon-to-come International Linear Collider (ILC) quartered in Japan and the ITER (International Thermonuclear Experimental Reactor) in France, as brought to light by Dr. Baskaran.

Such projects ease the burden on countries that wish they had the data from experiments but can’t provide the land to build the lab in the first place. In the case of CERN, the land belongs to two countries, the running costs to 69 nations, the responsibility to more than 7,300 physicists and engineers, and the experimental data to 6.6 billion people. Such overwhelming benefits require only a distributed investment model and cross-border trust to encash it. Alas, the last factor is the most impeding.

Consider the discovery of the super-luminary muon neutrinos detected at the Gran Sasso National Laboratory in Italy on September 23. In the absence of a unifying agency, the data would have been consumed by Italian researchers alone, keeping the world at bay for howsoever long it took to verify the results and get them published.

Now, a Puerto Rican or a Chilean has as much chance of explaining the phenomenon as does a Pakistani or Indian scientist. In fact, not only does the entire scientific community benefit by the sharing, but the chances of discovering something that will define the next big revolution are also increased.

(When asked about the strange occurrence, Dr. Baskaran asserted that owing to the small mass and low interactivity of the neutrinos, the existing energy generation technologies would not change as much our perceptions of the Universe. That, in turn, he said, will present new possibilities to produce more energy.)

A persisting sign of hope for India is its assistance with the construction of superconducting magnets at the LHC that even now are energizing beams of protons, and its significant contribution to the establishment of ITER. Further, Dr. Baskaran also revealed the news of a proposed Indian Neutrino Observatory (INO) at Theni, to be run by the government of India.

Alright, enough of taking comfort from the successes of the present; where are we headed? What does the future of science look like? The Tevatron has been closed, the baton has been passed to Europe to continue to look for the Higgs boson, the INO is under construction, and scientific representation is on the up. What about nanotechnology? It’s common knowledge that the Indians didn’t pay sufficient heed to Mr. Feynman. Is there still some space at the bottom?

We wouldn’t know, or, as Dr. Baskaran says, “There is nanomoney being spent on nanotechnology.” Employing India’s rise as an important centre for cheap but good medical care, he points out the important sectors our industries can capitalize on if it only took nanotech to the common man, akin to Gandhi’s talisman. There’s drug delivery, magnetic-resonance imaging, NEMS (nano-electromechanical systems), and, on another note, quantum computing. With continuing failure to look into these sectors, we're not only losing out on the international arena but we are also denying our citizens the opportunities to employment, to knowledge, to possibility.

So, are we again looking at the dearth of planning that has failed to incentivize the study of science in the country? Yes, at least in part. However, initiatives like InSPIRE – which is a 5-week long immersion program that reconnects Indians abroad to Indians at home – bear promise. On a final note, Dr. Baskaran insists that instead of continuing to depend on the government, which in turn depends on internally available resources, it is time to utilize the abundance of intellectual property within the nation and trust in the democracy of science.

Clear and present danger

“Revolutions in information and communication technologies have always been based on small findings in solid state physics” quips Dr. G. Baskaran, firmly establishing both the place and scope of technology. Affiliated with the Perimeter Institute in Waterloo, Canada, Dr. Baskaran is a renowned theoretical physicist. He recently delivered a short lecture at the Asian College of Journalism, speaking on everything from the role of science and the ongoing battle to explain super-luminary neutrinos to the future of science.

His statement couldn’t have come at a better time to remind the world of the necessity of science – and its techniques that we call technology. In the face of looming budget cuts in the USA and Europe, politicians and policy-makers have been raising serious questions about the necessity of everything from privately-owned small research labs to proposed upgrades to the Large Hadron Collider (LHC) at CERN.

The evolution of science and technology has been associated with greater unity amongst peoples, Dr. Baskaran said, and better health, wealth, education and opportunities to preserve our culture. “There is some responsibility also”, he adds with a confidence mature with experience.

With likely the greatest ICT revolution at its peak, his words suggest that the technology fuelling it is also maturing in the sense of its acceptance and social penetration. Perhaps it is time for the world to get on the wagon, increase its investments in R&D, and start saving up. The future it seems can stand only to gain because historical ties are snapping in the face of a rupture that is allowing previously-lagging nations like India and China give past-leader USA a run for its money. Increased capitalist traction in the form of tablet computers and smartphones should be thanked for this.

Perhaps the best example of such an opportunity is the increasing feasibility of multi-state-owned research laboratories. The pioneer in this regard is CERN, which was funded and built by 12 countries in 1954, a number that has increased to 20 since, and currently receives funding from 69 countries worldwide. Next in line are the soon-to-come International Linear Collider (ILC) quartered in Japan and the ITER (International Thermonuclear Experimental Reactor) in France, as brought to light by Dr. Baskaran.

Such projects ease the burden on countries that wish they had the data from experiments but can’t provide the land to build the lab in the first place. In the case of CERN, the land belongs to two countries, the running costs to 69 nations, the responsibility to more than 7,300 physicists and engineers, and the experimental data to 6.6 billion people. Such overwhelming benefits require only a distributed investment model and cross-border trust to encash it. Alas, the last factor is the most impeding.

Consider the discovery of the super-luminary muon neutrinos detected at the Gran Sasso National Laboratory in Italy on September 23. In the absence of a unifying agency, the data would have been consumed by Italian researchers alone, keeping the world at bay for howsoever long it took to verify the results and get them published.

Now, a Puerto Rican or a Chilean has as much chance of explaining the phenomenon as does a Pakistani or Indian scientist. In fact, not only does the entire scientific community benefit by the sharing, but the chances of discovering something that will define the next big revolution are also increased.

(When asked about the strange occurrence, Dr. Baskaran asserted that owing to the small mass and low interactivity of the neutrinos, the existing energy generation technologies would not change as much our perceptions of the Universe. That, in turn, he said, will present new possibilities to produce more energy.)

A persisting sign of hope for India is its assistance with the construction of superconducting magnets at the LHC that even now are energizing beams of protons, and its significant contribution to the establishment of ITER. Further, Dr. Baskaran also revealed the news of a proposed Indian Neutrino Observatory (INO) at Theni, to be run by the government of India.

Alright, enough of taking comfort from the successes of the present; where are we headed? What does the future of science look like? The Tevatron has been closed, the baton has been passed to Europe to continue to look for the Higgs boson, the INO is under construction, and scientific representation is on the up. What about nanotechnology? It’s common knowledge that the Indians didn’t pay sufficient heed to Mr. Feynman. Is there still some space at the bottom?

We wouldn’t know, or, as Dr. Baskaran says, “There is nanomoney being spent on nanotechnology.” Employing India’s rise as an important centre for cheap but good medical care, he points out the important sectors our industries can capitalize on if it only took nanotech to the common man, akin to Gandhi’s talisman. There’s drug delivery, magnetic-resonance imaging, NEMS (nano-electromechanical systems), and, on another note, quantum computing. With continuing failure to look into these sectors, we're not only losing out on the international arena but we are also denying our citizens the opportunities to employment, to knowledge, to possibility.

So, are we again looking at the dearth of planning that has failed to incentivize the study of science in the country? Yes, at least in part. However, initiatives like InSPIRE – which is a 5-week long immersion program that reconnects Indians abroad to Indians at home – bear promise. On a final note, Dr. Baskaran insists that instead of continuing to depend on the government, which in turn depends on internally available resources, it is time to utilize the abundance of intellectual property within the nation and trust in the democracy of science.