Within the left-right symmetric model (LRM) the decayswhere S 1 is an analog of the standard model Higgs boson, are considered. The widths of this decays are found in the third order of the perturbation theory. Since the main contribution to the decay widths is caused by the diagram with the light and heavy neutrinos in the virtual state then investigation of this decays could shed light upon the neutrino sector structure. The obtained decay widths critically depend on the charged gauge bosons mixing angle ξ and the heavy-light neutrinos mixing angle ϕ. The LRM predicts the values of these angles as functions of the vacuum expectation values v L and v R . Using the results of the existing experiments, on looking for the additional charged gauge boson W 2 and on measuring the electroweak ρ parameter, gives sin ξ ≤ 5 × 10 −4 , sin ϕ ≤ 2.3 × 10 −2 .However, even using the upper bounds on sin ξ and sin ϕ one does not manage to get the upper experimental bound on the branching ratio BR(S 1 → τ µ) exp being equal to 0.25 × 10 −2 . The theoretical expression proves to be on two orders of magnitude less than BR(S 1 → τ µ) exp .Keywords: Higgs boson, lepton flavor violation, left-right symmetric model, heavy and light neutrinos, mixing in the neutrino sector, Large Hadron Collider.
Within the left-right symmetric model (LRM) the Z boson decay into the channel Z → τ µ are investigated. The branching ratios of this decay is found in the third order of the perturbation theory. The obtained expression does not equal to zero only at the existence of the neutrino mixings. It means that from the point of view of the LRM nonconservation both of neutral and of charged lepton flavors has the same nature. As a result, elucidation of the decays Z → l i l k (i = k) could provide data concerned the neutrino sector structure of the LRM. The neutrino sector parameters which could be measured in that case are as follows: (i) difference of the heavy neutrino masses; (ii) heavy-heavy neutrino mixing; (iii) heavy-light neutrino mixing.Keywords: Z boson decays, charged lepton flavor violation, left-right symmetric model, heavy and light neutrinos, mixing in the neutrino sector, Large Hadron Collider.
The cross section of the process e+ e– → π+ π– π0 was measured with the CMD-3 detector at the electron-positron collider VEPP-2000 in the ω meson energy region based on the data collected in 2013–2018 and corresponding to an integrated luminosity of 40 pb–1. The parameters of the ω-meson: Mω = 782.67 ± 0.01 ± 0.1 MeV, Γω = 8.56 ± 0.02 ± 0.07 MeV, σ0(ω → π+ π– π) = 1629 ± 3 ± 36 nb with the precision match or even exceeding the previous data are obtained.
In this paper, we propose a method for the rejection of the background from the superposition of signals from different, almost simultaneously occurring events in the calorimeter for the COMET experiment. The basic idea is to use the chi-squared distribution obtained from fitting the recorded shape of the signal with an average waveform. The elaborated method is applied for the reconstruction of events with overlapping signals from the electron and radiative capture of neutrons by the 175Lu nucleus, as well as overlapping signals from two electrons born as a result of the decay of muons in the bound state with an aluminum nucleus with impulses causing a “false” signal of the μ – e conversion. The method showed a good ability to separate events, meanwhile, the separation time is significantly less than the FWHM of the pulse shape.
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