As soon as the discovery of the Higgs was announced in July 2012, there was immediate talk of who would get the seemingly inevitable Nobel prize for it, with some anticipating that it would be awarded even as soon as the same year. This did not happen and I personally did not expect it. For one thing, the Nobel committee is cautious and usually wants to wait until a discovery is totally nailed down before they honor it. Since the LHC has been shut down for a couple of years for upgrades, the corroborating evidence could take some time in coming, although further analysis of the data already taken indicates that the spin of the particle matches that expected of the Higgs. (For previous posts in this series, click on the Higgs folder just below the blog post title.)

The second reason that I did not expect it last year is because this issue is going to give the Nobel committee a big headache and it is going to take a while for them to figure out what to do. The reason for the difficulty is that although the discovery may be Nobel-worthy, the rules for the physics prize make things complicated. The conditions are that the winner has to be alive, no more than three people can share the prize and, unlike with the peace prize, it is not customary to award it to an organization, though that last one is a convention and not strictly against the rules, though there have been no exceptions so far.

So who are the people who are candidates? Recall that there were actually six theorists working more of less simultaneously who came up with the Higgs idea in 1964: Robert Brout, Francois Englert, Peter Higgs, Carl Richard Hagen, Gerald Guralnik, and Tom Kibble. The oldest was Brout who died in 2011 at the age of 83, but that still leaves five. There is a lot of politicking behind the scenes for Nobel prizes and it is unseemly when it comes out in the open and there are already grumblings from one of these theorists that the new particle should be called something other than Higgs so that recognition is shared more equally. One suggested name is the ‘SM Scalar Boson’, which strikes me as quite clunky and unlikely to catch on.

Because they are all getting on in years (the youngest of them is now 76 years old), the Nobel committee may not want to take too long in its deliberations in case more of them die, though a cynical view might be that it would make their job simpler if two of them did die. But the next oldest is Peter Higgs at 83 and if the Nobel committee dithers too long and he dies, that would be unfortunate. Although the others have a rightful claim to equal credit, the Higgs name is indelibly linked to this phenomenon.

But that is not all. The people who devoted a huge chunk of their lives to designing and constructing the LHC accelerator and the detectors, no mean feat, can also stake a claim to the award. The number of people involved runs into the thousands though if any experimentalists get it, it will likely be the leaders of the teams. But who can be considered the leaders? When it comes to constructing the LHC, Lynn Evans shepherded the project through all the challenging difficulties and could be the person chosen. But for the two detectors ATLAS and CMS, the leadership rotates. The two who happened to be the leaders at the time of the July 4 seminars where the discovery was announced were Fabiola Gianotti for ATLAS and Joe Incandela for CMS but would it be fair to give to them because of the fortuitous circumstance of having been put into the leadership position at the right time?

If the Nobel committee decides to break precedent and award a prize to an organization, then it may go to CERN, the home of the LHC and/or to the ATLAS and CMS detector teams.

Or they might decide it to award the prize to theorists and experimentalists in two separate years for the same phenomenon. There is a precedent for that. Back in 1979, the physics prize was awarded jointly to theorists Sheldon Glashow, Abdus Salam, and Steven Weinberg for, as the citation said, “their contributions to the theory of the unified weak and electromagnetic interaction between elementary particles, including, inter alia, the prediction of the weak neutral current”. The ‘weak neutral current’ referred to was what later came to be known as the Z particle. Then in 1984, the prize went to experimentalists Carlo Rubbia and Simon van der Meer for “their decisive contributions to the large project, which led to the discovery of the field particles W and Z, communicators of weak interaction”. In other words, the later prize was awarded for confirming the predictions of Glashow, Salam, and Weinberg.

But in that case, the theory prize had been awarded before the 1983 experimental confirmation of the prediction, which allowed for a natural sequencing of the two awards. That may have been because there was so much confidence that the work of Glashow, Salam, and Weinberg was correct that the actual detection of the W and Z particles was seen as important but inevitable. But in the case of the Higgs, no such certainty existed, right up until the moment it was found. But that means both theorists and experimentalists have become simultaneously eligible.

It is not sufficient to have merely confirmed a prediction, however significant, for an experimentalist to get a Nobel prize. You have to have done something novel and noteworthy as an integral part of the experiment. In the case of Rubbia, he came up with the idea of creating a beam of anti-protons that would rotate in a circle in the opposite direction to the protons in the Super Proton Synchroton (SPS), one of the predecessor accelerators to the LHC at CERN, and then having the two beams collide. This was new back then. van der Meer was an accelerator physicist who devised a way to create an intense beam of anti-protons. Creating such an intense beam was considered crucial to the success of the experiment.

Even then, there was some controversy about Rubbia getting the award. Like with ATLAS and CERN, that earlier experiment also involved two detector teams working independently (called UA1 and UA2) with Rubbia the leader of UA1. But unlike the recent situation where the two teams released their results simultaneously at a joint news conference, back in 1983 Rubbia, an intensely ambitious man, released his groups results a few weeks earlier and there was considerable acrimony over his scene stealing. It may be that it was to avoid that kind of unpleasantness that a joint seminar was held of both ATLAS and CMS teams,.

You can be sure that there is a huge amount of lobbying going on within the Nobel prize committee and there is bound to be considerable unhappiness with however the prize is awarded. The least acrimony would be if the prize committee bends the rules and awards it to the five remaining theorists but I do not know how flexible the system is.

Next: Concluding thoughts