That’s the main message that came out of the first large physics conference of the summer. After attending for several days all sessions of the European Physics Society meeting, hearing one report after another from the LHC and Tevatron experiments that the limits for the observation of all new and exciting phenomena besides the Higgs have been pushed yet even further can easily get to the hardiest physicist. But Professor Guido Altarelli, one of CERN’s leading theorist remains optimistic: “It’s too early to despair!” he said.
Asides from CMS and ATLAS reporting on small anomalies that could be interpreted as the first signs of the Higgs boson, it’s been low in the excitement department. No supersymmetric particles, no Hidden Valley or dark matter candidate, not even a new boson to munch on. Instead, impressive limits were set in so many new areas.
So eagerness is starting to affect many particle physicists. Never before have we had such a powerful accelerator delivering so much data, and detectors allowing the most precise and diversified measurements. With less than a year of data in, the LHC is already overtaking the Tevatron results in nearly all areas. After two decades in the making, it’s hard not to be chomping at the bit. But patience is really what we need. As Professor David Gross, a Nobel Prize winner and well-known theorist, reminded us: “We have one inverse femtobarn of data in, and 2999 more to go!” Much more data are coming and so will the new phenomena in due time.
Some theorists like Professor Altarelli excel at putting things in perspective and he too reminded us that we are just at the start of exploring the LHC capabilities. Looking at the way things are going, we will have the final word on the Higgs by the end of 2012. By then, we will have enough data to know for sure if the Higgs exists or if we should exclude it for good. We should also be able to explore every possible corner where supersymmetric particles could be hiding with the actual search strategy or even new ones.
This summer, I had the opportunity to spend a week at a theory workshop. Being the only experimentalist there, I spent plenty of time discussing what was going on in their camp. Clearly, they are not sitting idle while we are frantically searching our recently collected data for signs of new physics or the Higgs boson. On the contrary, many of them were already hard at work trying to find excuses for supersymmetry and reasons why it has not shown up yet as anticipated. Are we looking for it in the wrong way? Could our general approach be wrong? Many theorists I met already had new alternatives we could test.
It’s hard to be patient after waiting for all these great possible discoveries for so long. But as Prof. Altarelli reminded us, something is bound to happen: all the current theoretical knowledge indicates that we will either find a light Higgs boson (and we could already be on its heels), or we won’t. In either case, it will have to come with some new physics to explain dark matter or the hierarchy problem for example (why electrons are so much lighter that the top quarks). “New physics is guaranteed”, he said.
Dr Rolf Heuer, CERN Director General, even went further: “Finding or not finding the Higgs will be a discovery”, he reminded the audience. Excluding any of the theoretical models currently under test and setting new limits will enable us to progress in the right direction.
Theorists have their own worries. As Professor John Illiopoulos commented, at the rate the LHC is progressing, they only have a few months left to propose new ideas. “The time for speculations is over. The LHC is working!”
On the Higgs boson search front, Dr Bill Murray summarized the current knowledge following last week report of the possible first signs of a Higgs boson sighting. At this point, the situation could not be more ambiguous. We need more data, and to see the combined results. Both require a bit more time. But there is already enough hints to keep staring in that direction. I think we are seeing the caravan appearing in the far horizon. In just a few months, we will see it clearly or discover we all had sand in our eyes…
But given the amount of data analyzed so far, if the Higgs boson mass is really somewhere around 144 GeV, the small excess of events reported last week would be exactly what we would observe. A clearer picture will be given in late August at the Lepton-Photon conference in Mumbai.
Pauline Gagnon
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