It has been a busy week, but I cannot let it pass without saying a brief word about the Higgs boson discovery at CERN. This is something that everyone has been expecting since the lab was upgraded to higher energies a few years ago. In other words, it is not a surprise — and, in fact, from a certain point of view it would have been more exciting if they had not found it. I will even admit that I was feeling a little blasé as the rumours of the discovery began to circulate in recent months.
That changed, however, when I saw this:
It is real!
The official scientific paper describing the findings has not been published yet, but CERN is reporting the discovery of a boson (a particle with integer spin) with a mass of about 126 GeV (as in the figure above). The mass is roughly equivalent to that of an iodine atom, making the Higgs boson the second heaviest known elementary particle (after the top quark).
The extent to which the properties of this new particle match those predicted by our theory will take time to sort out. Measuring the spin will be an obvious first step, if it hasn’t been done already. Its couplings to the other particles will have to be measured. In other words, a lot of work will be done to check whether this Higgs boson is the one we expected to find.
Many physicists are hoping that it is not. The cost to build and run these collider experiments is so enormous that if the current facilities at CERN find the Standard Model Higgs boson, and nothing else, there is considerable worry — well-founded worry, in my opinion — that the era of collider physics, which has taught us so much, will be over. The political will to build another, bigger, more expensive experiment will not exist.
If, on the other hand, there is something odd about this Higgs boson, or if CERN finds something else — something unexpected — in the next few years, then our theory will need revision, and more experimental studies will be needed to sort things out. That is an argument to keep going.
Despite those worries, this is a time for celebration. I think especially of the thousands of people who have worked so hard, for so long, to get to this point. The complexity and scale of these experiments beggars description; they are truly amazing feats of design and engineering, and those responsible for them can be justly proud at a time like this. All that work, and we reap the harvest.
This video gives an accessible but informative introduction to the Higgs boson. It takes a minute or so to really get going, and it looks better when viewed at full-screen.