How to convert a muon into an electron?

About the commitment to discover the neutrinoless conversion

Following the discovery of neutrino oscillations, experiments on the search for neutrinoless muon-to-electron conversion have started in the United States and Japan. Such a conversion would violate the customary law of conservation of lepton numbers of both particles and can be expected to occur only in the field of nucleons inside an atomic nucleus. For this to happen, a muon should be captured by the nucleus, which is possible if we first slow down the muon by sending it into an elongated piece piece of metal such as aluminum. When the muon is nearly stopped there, it can be trapped in atomic orbit, similarly to electrons. If the muon does not have time to decay in orbit in the usual way, emitting neutrinos, it will be captured by the nucleus, where there is a chance of neutrinoless electron emission. A beam of muons is produced from decays of pions also flying in а beam that is formed by bombarding with protons, for example, a graphite target. There should be very many muons in the beam, because in similar experiments in Switzerland it has been found that the probability of the neutrinoless conversion does not exceed one to one hundred thousand billion.

A superconducting solenoid for an experiment on the search for neutrinoless muon to electron conversion

The magnetic field directs muons to the target along a curved superconducting solenoid while unwanted particles fly straight.


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