At the end of last year, two different tools on a massive subatomic particle accelerator, which is known to us as the Large hadron Collider (LHC), saw something. No one knows what has caused the upsurge of data — it came from pairs of photons that collided in the detectors at the same time with the same energy. By studying such collisions in the opposite direction, physics find out the details of the death and decay of larger particles. Usually.
But at that time it was not so simple. New “di-photon excess” — unpredictable and unexpected — could indicate a particle is four times heavier than the heaviest known particle, the top quark, and six times heavier than the famous Higgs boson. It may indicate the existence of a relative heavy Higgs or the graviton is still a theoretical particle that transmits gravity. Or it could be something completely new, a harbinger of new physics.
Well, nothing — the statistical error of the phantom generated by the machine.
Following the launch of the LHC in April should provide the answer. But particle physics — an impatient people. In anticipation of new data, they work hard, shelling out hundreds of works on site arXiv.org in an attempt to explain yet statistically insignificant data. New particle? What would it mean? What should it be?
Of course, physics can just wait for the sea weather and no steam. But they don’t want.
The shock of the new
“That’s the spirit of theoretical physics, says Jean Judes, a theoretical physicist at CERN and the author of one of the works which caused the greatest sensation. — You take the data at your disposal, and then start thinking, if they fit under your view of the Universe.”
Then you start thinking how to test these ideas. Get more data. See how they correspond to the original ideas and perhaps change them. “On and on, says Judis, — until you get the true history of our Universe”.
However physics don’t jump on each anomaly, like a Dachshund on a hamster. Strange dips and spikes in the data appear constantly, and yet physics is not thrown every time write operation, said Michele Redi, a theoretical physicist at the National Institute of nuclear physics in Florence and one of the authors Iudica. “But this case smells different,” he says.
First, the bursts showed data from two different instruments. This in itself indicates the validity of the event that is the artifact in some way. But more importantly, and this second, if these results are real, they can flip or at least to extend the Standard model, the theoretical basis of which was developed in the 1970s, and which explains the interaction of particles. “The standard model of elementary particles has been very successful in describing interactions of all particles, which we directly observed in nature, said Rob McPherson, spokesperson of the ATLAS instrument, one of the two detectors, which catch the signal. But for some questions the answers she gives.”
The standard model is good, and so far, experimental physics has confirmed its length and breadth. But she explains not all: there are gaps and mysteries like dark matter, antimatter and gravitation.
Therefore, physicists are desperately waiting for the Standard model of the crackling at the seams. This would give them a chance to develop a new version — and build a new understanding of the Universe. In the end, most modern theorists have not worked in the 70-ies and I remember the excitement that was in the early stages of development CM.
Race
For many years the chance to turn the Standard model seemed highly questionable. It seems that the TANK dumps megatons of data on the old physics and no new icons. “Simply put, no one in our field and an ounce of hope seemed to be cherished, says Redi. But along with the surge December 15, everything changed. The smell of new physics point to the fact that here it, around the corner, just within arm’s reach. Redi and his colleagues worked around the clock to select it and “publish” first.
Mihajlo Bakovic from Catholic University in Belgium, who wrote a work on fever struck scientists: “the Excess of di-photons illuminates dark matter”. He is well aware that this is only an exercise in speculation. “First of all, the reason why theoretical physicists are doing something in physics, is that it’s fun, says Bakovic. Is the only reason why we are here — to meet our children’s expectations about the Universe.”
Part of the fun, however, is the opportunity to be the first to discover something new. The majority of scientific discoveries — I’m sorry, science is a routine, everyday life. Very rarely change the paradigm. And even less often this shift occurs in public, when the results themselves are asked to interpret. If scientists wait for confirmation of a burst of data, without participating in the theorizing, they will not be able to be the first. “The ownership of ideas in our day defined by the day — perhaps an hour — supply work, says Bakovic, so people feel the need to publish their speculation above the rest.”
When a colleague sent Bukovica chronological story about how much work he and his fellow-theorists threw on arXiv during this time (as of 10 March was 276), he also dived into the data. “I was struck by the fact that the curve looked surprisingly regular, and I thought, if I can see its shape, he says. — So I began to do the same as other physics: play with data in an attempt to make a model.”
During the daily visits, Bakovic fiddled with statistics, trying to find a mathematical representation which would show how many papers have appeared over time, and predicts how this will change in the future. It turned out that we need only two assumptions: that people’s interest in the excess of di-photons and the number of ideas that have left to write will decrease as time passes. “I thought that would be perfect to show that something that seems very difficult, due to human behavior, it is possible to simulate very simple math,” he says.
Bakovic came to the conclusion that until June 10, you should receive about 310 papers. In the Preface to the work, he thanked the Belgian railway lines because they provided him with a comfortable environment on the road, where the work was carried out, and frequent delays of trains added time. Bakovic assesses the chances of the existence of a new particle in 20%.
Redi is a bit more optimistic. “It is very difficult to say and many refuse to bet, he says. But I like this game, so if I had to bet money I would say the probability is 50%”.
Judis refused to bet. Supposedly he’s not looking into a crystal ball and sees the future.
MacPherson, on the contrary, looking at the past. He saw such “hints” of physics beyond the Standard model for several decades. “Until now they have all disappeared with more precise analysis and additional data,” he says. Large electron-positron Collider saw what some believed to be the hints of the Higgs. But it didn’t happen. The data were even better (more significant) than the recent spike, says McPherson, but was a random fluctuation in the background. After that, the Higgs remained undiscovered for more than a decade.
In its work, Bakovic analyzed the patterns of publication after eight other high-profile situations in physics. The initial surge (and related document) is not signaled future success. On his list were the BICEP2 observation in support of cosmic inflation, and also as evidence of the movement of neutrinos faster than light — both events proved to be empty.
Anyway, nobody will lose, says Bakovic. If the splash would be a Fluke, all will benefit from discussion and mental gymnastics. “If a physicist complains that it’s a waste of time, he chose the wrong profession,” he says.
Appropriate tools TANK will be back to work in April. The summer will be collected as much data as the TANK is collected for the whole of 2015, and by the end of summer — twice. MacPherson says that they hope to get the final answers by the beginning of the International conference on high energy physics in August.