Neutron dark matter decays and correlation coefficients of neutron β--decays

As we have pointed out in (arXiv:1806.10107 [hep-ph]), the existence of neutron dark matter decay modes n -> chi + anything, where chi is a dark matter fermion, for the solution of the neutron lifetime problem changes priorities and demands to describe the neutron lifetime tau(n) = 888.0(2.0) s, measured in beam experiments and defined by the decay modes n -> p + anything, in the Standard Model (SM). The latter requires the axial coupling constant lambda to be equal to lambda = -1.2690 (arXiv:1806.10107 [hep-ph]). Since such an axial coupling constant is excluded by experimental data reported by the PERKEO II and UCNA Collaborations, the neutron lifetime tau(n) = 888.0(2.0) s can be explained only by virtue of interactions beyond the SM, namely, by the Fierz interference term of order b similar to-10(-2) dependent on scalar and tensor coupling constants. We give a complete analysis of all correlation coefficients of the neutron beta(-)-decays with polarized neutron, taking into account the contributions of scalar and tensor interactions beyond the SM with the Fierz interference term b similar to-10(-2). We show that the obtained results agree well with contemporary experimental data that does not prevent the neutron with the rate of the decay modes n -> p + anything, measured in beam experiments, to have dark matter decay modes n -> chi + anything. (C) 2018 The Author(s). Published by Elsevier B.V.