Probing the Lμ - Lτ gauge boson at the MUonE experiment

We discuss the prospects of probing the L-mu - L-tau gauge boson at the MUonE experiment. The L-mu - L-tau gauge boson Z' with a mass of less than or similar to 200 MeV, which can explain the discrepancy between the measured value of the muon g - 2 and the value calculated in the Standard Model, can be produced at the MUonE experiment through the process mu e -> mu eZ' . The Z' in the final state decays into a pair of neutrinos, and therefore we cannot observe the decay of Z' directly. It is, however, still possible to probe this signature by searching for events with a large scattering angle of muon and a less energetic final-state electron. The background events coming from the elastic scattering lee ye as well as radiative process mu e -> mu e per can be removed by the kinematical cuts on the muon scattering angle and the electron energy, in addition to a photon veto. The background events from the electroweak process mu e -> mu e nu(nu) over bar are negligible. With our selection criteria, the number of signal events mu e -> mu eZ' is found to be as large as similar to 10(3), assuming an integrated luminosity of 15 fb(-1), in the parameter region motivated by the muon g - 2 discrepancy. It is, therefore, quite feasible to probe the L-mu - L-tau gauge boson at the MUonE experiment-without introducing additional devices-and we strongly recommend recording the events relevant to this Z' production process.

Automated summary

The prospects of probing the L-mu - L-tau gauge boson at the MUonE experiment are discussed. The study focuses on the production of the Z' boson and its decay into neutrinos. Although the direct observation of the Z' decay is not possible, it is feasible to detect this signature by looking for events with specific scattering angles and energy distributions. The background events can be effectively eliminated through kinematic cuts and photon vetoes. The study suggests that it is quite possible to probe the L-mu - L-tau gauge boson without additional devices and recommends recording the relevant events.