My kingdom for a neutrino

In 1982, when the construction for CERN’s Large Hadron Collider (LHC) experiment was given the go-ahead, physics entered a very exciting period. It promised them the answers to their biggest questions and, in the event that that didn’t happen, it promised them ample evidence to come to a conclusion of their own.

Two decades later, with the device in full operation, results are emerging, some more improbable than the rest. The project was put in place to attempt to create the conditions of the Big Bang so physicists could detect the Higgs boson. However, nobody anticipated such a thing as evidence of super-luminary travel by neutrinos.

The existence of neutrinos was first proposed by Austrian physicist Wolfgang Pauli in 1930 to account for the excess mass and energy left behind after a neutron disintegrated into a proton and an electron. The first direct observation was to be made only in the 1970s, more than 40 years later. The neutrino is one of the many indivisible particles of this Universe, and is of neutral charge and very little mass. In fact, amongst all the particles that have any mass, a neutrino is the lightest. This means that according to Albert Einstein’s theory of relativity, the mass of the particle will hit infinity only when it travels at speeds terribly close to that of light. And by terribly close, I’m talking 99.9999% close.

Such neutrinos were generated by the LHC over the course of some of its experiments and sent to the Gran Sasso National Laboratory in Italy for study. Located 730 km south of the LHC and almost a kilometre under Mt. Gran Sasso, the laboratory receives the particles in a massive tank of ultra-pure water.

Once a neutrino comes in contact with a proton of a water molecule, they react to form a neutron and a positron. The positron collides with an electron, its anti-particle, to annihilate each other, releasing two gamma rays. The neutron is captured by another nucleus to release a third gamma ray. Therefore, the signature of a neutrino capture is the release of three gamma rays.

[caption id="attachment_20371" align="aligncenter" width="439" caption="The Super-KamiokaNDE experiment in Japan contains a tank of 50,000 litres of water, fit with an array of tens of thousands of photo-multiplier tubes (as above) to detect the release of energy in case of a neutrino capture. The cylindrical container has other systems in place to detect the position of a capture, too."][/caption]

At the laboratory, as scientists waited for the neutrinos to arrive and set off the reactions, they were hardly prepared when the release of the gamma rays was detected precisely 60 nanoseconds before it was due. While such a small difference might seem trivial, the implication is that the neutrinos arrived before any other kind of electromagnetic radiation did. Since electromagnetic radiations possess the fastest speed attainable in this Universe according to Einstein, the speeding neutrinos have possibly defied the greatest physicist of the last century.

Where does that leave the world of physics?

Centuries of hypothesizing and experimenting by scientists have ingrained the importance of reasoned scepticism in their minds. While the Gran Sasso National Laboratory has claimed that 16,000 such instances have been recorded and documented, they haven’t ruled out any errors. For now, physicists the world over await similar conclusions, and so confirmations, from the two other colliders capable of replicating such conditions.

One of them is the J-PARC in Japan. Located along the coast of the Tohoku prefecture, the device was damaged and unable to operate for the next 12 months, at least, by the earthquake in March 2011 in nearby Fukushima. The other collider is the Fermilab Tevatron, an atom-smasher of considerable reputation, in the USA. After close to three decades of operation, the facility is scheduled to shut down permanently on September 30, 2011.

Collaboration rather than competition seems to be the emerging mantra. The shadow of CERN is beginning to loom large on most particle physics labs, and they’re finding it difficult to compete with CERN and its flagship project. Further, in these days of ballooning fiscal deficits and bond rating downgrades in the US, funding is hard to come by for such "creamy" projects.

Unsurprisingly, physicists are prepared to wait. Why won’t they when the speed of light – a form of electromagnetic radiation – has been the definitive cornerstone of some of the most important foundations of our understanding of this Universe? By defying that limit, neutrinos have brought upon them the scrutiny of the entire scientific community.

For one, by being faster than light, neutrinos speeding toward Earth from distant stars get here before the image of the star does, making it possible for astrophysicists to peek farther back into history. Second, the particle that carries electromagnetic energy, the photon, was thought to be massless so it wouldn’t violate the theory of relativity. However, the neutrino has mass, and that means all of Einstein’s works will have to be disrobed and studied. The larger consequence of this is that almost all high-energy installations on this planet, ranging from nuclear power plants (NPPs) that power cities to radio-telescopes searching for extra-terrestrial life, become available for changes as much as at the design level.

(In an NPP, the flow of single-phase coolants in pressurized water reactors is assumed to flow not faster than the speed of light. Even if the fluid dynamics of single-phase coolants has already been modelled on luminary principles, how could there be any changes at the design level?

If the speed of the coolants can be increased even higher, then the critical discharge, i.e., the maximum flow rate permissible, will also go higher. This translates into enhanced cooling, and this obviously means that fuel rods can be made even thicker and more power could be generated.*)

Similarly, the way the world works also is not going to change since the neutrino has always been working the same way for billions of years irrespective of how we thought it worked. But what is going to change is the way we understand electromagnetic concepts. The Standard Model of particle physics, the Big Daddy of all the theories of physics, won’t have to be tweaked so much as twisted around to accommodate this yet-unsubstantiated phenomenon.

Physicists will wait, and while they wait, they’ll debate. They’ll conduct more experiments, record more data, hypothesize more, refute more, argue more, all the while hoping that the Tevatron will be fired up for one last battle, that the J-PARC will be resuscitated for a one-of-a-kind challenge. In my opinion, no overbearing modifications will have to be made to the pool of knowledge we possess regarding physics as such. Even if the neutrinos did travel at super-luminary speeds - which I highly doubt and attribute to minute measurement errors adding up to cause the spike - it won't be long before the concept of the phenomenon is quickly subsumed by the search for other even greater truths. Yes, our perspectives are going to change, but more than anything, the discovery's original role as a tool with which to discover more about nature will not.

Let's not get carried away, though. After all, disproving the greatest minds of physics in history requires a future of its own.

*On the other hand, for example, the speed at which the gravitational force acts on any body is limited to the speed of electromagnetic radiations, but that doesn't mean discovery of a higher speed in this Universe is going to change anything. It's only a role reversal at the most (although the massiveness of the neutrino is going to make a difference) because the practically achievable velocity is going to remain the same.