Precision analysis of pseudoscalar interactions in neutron beta decays

Abstract

We analyze the contributions of the one-pion-pole exchange, caused by strong low-energy interactions, and the pseudoscalar interaction beyond the Standard Model (SM) to the correlation coefficients of the neutron β − -decays with polarized neutrons, polarized electrons and unpolarized protons. We show that the contribution of the one-pion-pole exchange is of order 10 −5 . The contributions of the one-pion-pole exchange and the pseudoscalar interaction beyond the SM are compared with the contributions of G-odd correlations or the contributions of second class hadronic currents of order 10 −5 calculated by Gardner and Plaster (Phys. Rev. C 87, 065504 (2013)) and by Ivanov et al. (Phys. Rev. C 98, 035503 (2018), Phys. Rev. D 99, 053004 (2019)). We find that in case of vanishing tensor and pseudoscalar interactions beyond the SM the Fierz interference term b can be induced of order b ∼ 10 −5 by the one-pion-pole exchange, caused by strong low-energy interactions.

Corrections of order O(E^2_e/m^2_N), caused by weak magnetism and proton recoil, to the neutron lifetime and correlation coefficients of the neutron beta decay

“…The electron-energy and angular distribution of the neutron beta decays for a polarized neutron, a polarized electron and an unpolarized proton was given by Jackson et al [39]. Following [17,18,[25][26][27] it can be written in the following form (see also [37] with a replacement λ = −g A )…”

“…where we have followed the notation [18,[25][26][27]37]. Then, ξ n and ξ e are unit polarization vectors of the neutron and electron [25,26] (see also [38]), respectively, dΩ e and dΩ ν are infinitesimal solid angles in the directions of electron k e and antineutrino k ν 3-momenta, respectively,…”

“…Following [18,[25][26][27]37] we calculate the complete set of corrections defining the total corrections ζ(E e ) (N 2 LO) and X(E e ) (N 2 LO) to the correlation function ζ(E e ) and correlation coefficients X(E e ) for X(E e ) = a(E e ), A(E e ) and so on. We would like to notice that all corrections of order O(E 2 e /m 2 N ) to the correlation coefficients D(E e ), R(E e ) and L(E e ) are either equal to zero or much smaller than 10 −5 .…”

Radiative corrections of order O(αEe/mN) to Sirlin’s radiative corrections of order O<

“…4. Since, as has been shown in [62,63], the RC to the one-pion-pole exchanges are of the order of 10 −9 (see also [66]), we omit them from consideration. The analytical expressions for the Feynman diagrams in Fig.…”

Electrodisintegration of Deuteron into Dark Matter and Proton Close to Threshold

“…We would like to emphasize that a possibility to explain the NLA problem by the neutron dark matter decay mode n → χ + ν e + νe is not innocent and demands to pay the following price. As has been pointed out in [9], the explanation of the neutron lifetime τ n = 888.0(2.0) s [1] within the Standard Model with the axial coupling constant g A = 1.2764 [28,29], reproducing the neutron lifetime τ n = 879.6(4) s [30], is not possible and demands the account for the contributions of interactions beyond the Standard Model such as the Fierz interference term b [31][32][33][34][35][36][37][38] equal to b = −1.44 × 10 −2 [39]. However, as has been shown in [39], the Fierz interference term b = −1.44 × 10 −2 does not contradict the existing experimental data on the correlation coefficients and asymmetries of the neutron beta decay.…”