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Once thought to be possible to "break the standard model"Muon, was pressed back by scientists.
After strictly reviewing the experimental data, the LHCb team from Europe admitted that there were problems in the previous analysis:
In fact, the results and the prediction of the standard model areconsistentYes.
You know, once this heavy discovery is confirmed, there may be a new theory that subverts the standard model, and even the whole particle physics system will be rewritten.
Now, however, this series of results has once again proved unreliable-
The key evidence of the so-called "muon abnormality" is due toA series of subtle errorsCaused.
Chris Parkes, a spokesman for the LHCb team and a physicist at the University of Manchester in the UK, explained:
In earlier measurements, scientists mistakenly identified some other particles as electrons.Although the Large Hadron Collider (LHC) can capture muons well, it will be more difficult for them to detect electrons.
This is not good news for many physicists who try to overthrow the existing theory.
But even so, they did not give up trying to explore new theories.
Was once considered to subvert the standard model.
Standard model, a physical model to explain quarks, electrons and other microscopic particles, is regarded as one of the most successful physical theories in history.
Since the Higgs boson was discovered 10 years ago, all the particles predicted by the standard model have been discovered.
According to the prediction of the standard model, different charged leptons-electrons, muons and τ-only have different masses, and other properties (such as charge and spin) should be exactly the same, which is called lepton taste universality (LFU).
However, the LHCb team has been trying to find anomalies to break the standard model. In the past few years, they have published many papers and put forward measurement results that may violate LFU.
For example, in a paper in 2021, the team studied the decay process of B meson about K meson based on LFU theory.
Originally, the probability of producing electrons and muons in this process should be equal, but the measurement found that the probability of producing muons was 85% of that of electrons, and the confidence reached three standard deviations (3σ).
Although it is not 5σ that can be used to claim important discoveries, it is surprising enough.
BUT, after a long review for one year, the LHCb team found that the experimental result isexist problemYes.
When re-examining the data related to the decay process of the B meson of the K meson, the LHCb team realized that this anomaly was caused by a series of subtle errors.
They made this result public at the seminar of CERN on December 20th, which also surprised many physicists.
Gino Isidori, a theoretical physicist at the University of Zurich, said that this result is really unexpected, because outliers really seem to mean "Particles that have never been seen beforeThe existence of ":
I regret this result, but it is still commendable for LHCb to "honestly" disclose this result.
Making muons and studying muons
In fact, it is already "frightening" for scientists.MuonThe routine operation.
But since it is still one of the best hopes to break the standard model, physicists do not intend to give up their research on it.
A new study recently published in the journal Nature shows that scientists are looking for a new way to measure the properties of muons, that is, to make a strong muon particle beam to reduce statistical errors.
Among them,Muon elementMuon even element (symbol Mu, muonium), also known as muon even element, is a strange atom with electrons rotating around positive muons, which is a very suitable model for studying muons.
It is not easy to produce a large number of muons, but scientists from the Paul Scheler Institute (PSI) in Switzerland and the Federal Institute of Technology in Zurich have successfully achieved this.
They used microwave and laser to detect the characteristics of muons formed on low-energy muon beams, and measured the transition between some very specific energy sub-levels in muons for the first time.
The team’s next goal is to weigh muons, that is, to further weigh muons with higher accuracy as the basis for calculating other experimental constants. The researchers said:
If the experiment goes well, we may improve the measurement accuracy by another 100 times.
In this series of measurements, new characteristics of muons may also be discovered, which may "challenge" the standard model again.
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