Exploring neutrino mass and mass hierarchy in the scenario of vacuum energy interacting with cold dark matter

We investigate the constraints on total neutrino mass in the scenario of vacuum energy interacting with cold dark matter. We focus on two typical interaction forms, i.e., Q=βHρ_c and Q=βHρ_∧. To avoid the occurrence of large-scale instability in interacting dark energy cosmology, we adopt the parameterized post-Friedmann approach to calculate the perturbation evolution of dark energy. We employ observational data, including the Planck cosmic microwave background temperature and polarization data, baryon acoustic oscillation data, a JLA sample of type Ia supernovae observation, direct measurement of the Hubble constant, and redshift space distortion data. We find that, compared with those in the ∧CDM model, much looser constraints on ∑m_ν are obtained in the Q=βHρ_c model, whereas slightly tighter constraints are obtained in the Q=βHρ_∧ model. Consideration of the possible mass hierarchies of neutrinos reveals that the smallest upper limit of ∑m_ν appears in the degenerate hierarchy case. By comparing the values of χ_min², we find that the normal hierarchy case is favored over the inverted one. In particular, we find that the difference △χ_min² ≡ χ_{IH; min}²-χ_{NH; min}² > 2 in the Q=βHρ_c model. In addition, we find that β=0 is consistent with the current observations in the Q=βHρ_c model, and β < 0 is favored at more than the 1σ level in the Q=βHρ_∧ model.     

Inverted neutrino mass hierarchy and new signals of a chromophobic charged Higgs at the Large Hadron Collider

We explore the signals of a charged Higgs arising in a two Higgs doublet model respecting SUL₍₂₎×U(1)×Z₂$\mathit{SU}{(2)}_L\times U(1)\times Z_2$ symmetry with three singlet right-handed neutrinos, NR$N_R$. The charged Higgs in this model has negligible coupling with quarks, and has unsuppressed coupling to leptons and neutrinos. This leads to novel signatures of the charged Higgs at the LHC, especially in the case of an inverted neutrino mass hierarchy, in the form of electrons and muons with missing energy.     

Interference effects in X-ray radiation from relativistic electrons moving at a small angle to an atomic plane

X-ray radiation of relativistic electrons interacting with a set of parallel atomic planes is considered. The anomalous behavior of the radiation due to the interplay of parametric and coherent bremsstrahlung emission mechanisms, which simultaneously occur under specific conditions, is studied.     

New version of the integrated method for measuring small effects in experiments on beams extracted from a nuclear reactor at the effect sign switching frequency above the fundamental frequencies of the reactor power fluctuation spectrum

The principles of construction and the results of testing of a system for measuring P-odd asymmetries in nuclear reactions with polarized cold neutrons by the integrated method of recording events at the neutron polarization switching frequency above the fundamental frequencies of the reactor power fluctuation spectrum are presented. It is shown experimentally that if the signal under investigation is characterized by the spectral density of power decreasing with increasing frequency, switching of the equipment at a higher frequency decreases the measuring error. The dependence of the error of measurements of P-odd asymmetry in the emission of γ quanta in the ¹⁰B(n, α)⁷Li* ⟹ γ ⟹ ⁷Li(g.s.) reaction on the neutron polarization switching frequency is derived. The system described here is implemented experimentally for the first time.