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Suspicion of the existence of a particle 6 times heavier than the Higgs that does not fit the standard model

Two separate experiments at the Large Hadron Accelerator in Sarn, Atlas and CMS revealed differences in the decay products carried out after increasing the accelerator's power to 13 tera electron volts * Prof. Elam Gross: It should be emphasized that apparently this is a statistical fluctuation because in both experiments the results are not significant, but the fact that they They were discovered in the same suspicious environment

A collision event that produced a pair of photons observed by the CMS detector on the axis
A collision event that produced a pair of photons observed by the CMS detector on the axis

Two separate experiments at CERN discovered "jumps" with a mass of 750-760 giga-electron volts, for comparison, the mass of the Higgs boson discovered in 2012 is about 125 giga-electron volts, that is, if there is a particle with a mass of about 750 giga-electron volts It is six times heavier than the Higgs. These discoveries were published one after the other at a public event at the Sarn facility near Geneva, yesterday (Tuesday).

Since April of this year, the LHC accelerator has been operating at high power - 13 tera electron volts, in what is known as run 2. In the first run, since its activation and more precisely since the malfunction that occurred shortly after the first run, it was only operated at 7 and then at 8 tera electron volts , which was enough to discover the Higgs boson.

Now, ahead of the shutdown of the accelerator for the winter period, the representatives of Atlas and CMS, the two largest experiments out of the four that operate in the event axis, convened, and mainly said that no result contrary to the standard model in physics was obtained, when they repeated the experiments in which particles were discovered in the past, except for the Higgs, for which there is still not enough data to restore it.
It seems that the first hints of new physics that came up at the end of the first run have disappeared in the meantime, but there is still a hint of the possibility of the existence of a new particle. First up was Jim Olsen from Princeton University participating in the CMS team. He began by listing results that confirm the Standard Model of particle physics—a good way to confirm that the accelerator is working as intended. "The standard model at this early stage is still solid," he said. As mentioned, he added that there is not enough data to "rediscover" the Higgs, but this will be possible next year.

According to him, towards the end of the first run - before the downtime for upgrading in February 2013, both Atlas and CMS discovered weak evidence for the existence of a boson with a mass of 2 tera electron volts (TeV) much heavier than the Higgs - 125 giga electron volts. However, in the new run CMS did not see these signs again, "We do not have enough data to rule out its existence, but it still seems possible that the previous signals were just beeps. There is still no evidence for the existence of a potential particle with super symmetry known as "the edge". Super symmetry or (SUSY) is a theory that extends the standard model with heavier particles and finding it is one of the goals of the second run.

But as mentioned, there is still hope for a new particle. Olsen presented results showing a sequence of events that produced two photons at 750 giga-electron volts, which may indicate the existence of a new particle. However, the result has a statistical significance of 2.6 standard deviations, close to the particle physics criterion of 3 standard deviations where the results start to be "interesting." But still far from the 5 standard deviations needed to declare a discovery. If you consider that you get a good result because there are a large number of possible events being looked for, this reduces the significance to 1.2 so it could still be nothing.

He was followed by Marumi Kado of the Linear Accelerator Laboratory in Orsay, France, on behalf of the Atlas Group. He also confirmed the stability of the standard model, and even managed to see signs of the existence of the Higgs even at the new intensity, but this is still not clear. According to him, no sign of the existence of SUSY was found either. They actually discovered hints of the existence of "the edge", but they were less distinct than in the first run. According to the two, the fact that both experiments found similar signals shows that there is a chance for a particle on the horizon in 2016, but it may still be a fluke.

The Israeli point this time - one of the main scientists who performed the analysis Dr. Liron Barak, the first Israeli with the status of a Saran fellow, since Israel was accepted as a Saran member about two years ago.

Professor Elam Gross from the Weizmann Institute, a particle physics researcher who headed the Higgs discovery group in the Atlas experiment, was not involved in this analysis, although the data analysis was performed according to a statistical model he developed together with Ofer Vitales. In an interview with the scientist website after attending the event in Geneva, Prof. Gross said:

"It is a fluctuation in the 750-760 GeV region that both Atlas and CMS see. The measurements match. The problem is with a particle that decays into two photons - it is a heavy particle that does not fit into any known model, so there are many doubts."
In response to the question of what the properties of a particle with such a mass might be, Prof. Gross said: "It is impossible to estimate (its AB properties) because this is a very unexpected discovery. I guess the theorists will come up with their own hypotheses very soon.

"From an experimental point of view, this is very interesting because if it is a statistical fluctuation, why did it appear in both Atlas and CMS in the same mass? The fact that it appeared in the same mass reduces the "Look Elsewhere" effect.
"The effect speaks of the fact that even if there is a fluctuation at 750 GeV, if it appeared at any other mass we would also draw attention to it. So the question is not: what is the chance of fluctuation at 750 (which is very low, Atlas got almost 4 sigma and if you add CMS it will be a smaller chance - that is, higher significance). The question is what are the chances of seeing a fluctuation in some kind of mass. And of course this is a higher chance that reduces the significance of Atlas to about 2 standard deviations, which is no longer something for which a press conference is held. But you have to remember that every discovery starts like this. In my estimation, this is probably a statistical fluctuation, but a very unusual one and one that we will need at least six months, if not more, to collect data again and find out."

More of the topic in Hayadan:

6 תגובות

  1. In fact, Dr. Liron Barak from the Weizmann Institute is a partner in the experimental team. She did her PhD with Elam Gross at the LHC. Now he is using being Rt Atlas (?) and his relationship with her as a research fellow, to announce the announcement. Science is cold in the sense that the next famous discovery is not necessarily with the famous professor.

  2. Thanks for the article - it's always interesting to hear about things that are not in my area of ​​knowledge.

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