We give a precision analysis of the correlation coefficients of the electron-energy spectrum and angular distribution of the β − -decay and radiative β − -decay of the neutron with polarized neutron and electron to order 10 −3 . The calculation of correlation coefficients is carried out within the Standard model with contributions of order 10 −3 , caused by the weak magnetism and proton recoil, taken to next-to-leading order in the large proton mass expansion, and with radiative corrections of order α/π ∼ 10 −3 , calculated to leading order in the large proton mass expansion. The obtained results can be used for the planning of experiments on the search for contributions of order 10 −4 of interactions beyond the Standard model.

We calculate the correlation coefficients of the electron-energy and electron-antineutrino angular distribution of the neutron β −-decay with polarized electron and unpolarised neutron and proton. The calculation is carried out within the standard model (SM) with the contributions, caused by the weak magnetism, proton recoil and radiative corrections of order of 10 −3 , Wilkinson's corrections of order 10 −5 [Wilkinson, Nucl. Phys. A377, 474 (1982) and Ivanov et al., Phys. Rev. C 95, 055502 (2017)] and the contributions of interactions beyond the SM. The obtained results can be used for the analysis of experimental data on searches of interactions beyond the SM at the level of 10 −4 [Abele, Hyperfine Interact. 237, 155 (2016)]. The contributions of G-odd correlations are calculated and found at the level of 10 −5 in agreement with the results obtained by Gardner and Plaster [

We present phase shift measurements for neutron matter waves in vacuum and in low pressure Helium using a method originally developed for neutron scattering length measurements in neutron interferometry. We search for phase shifts associated with a coupling to scalar fields. We set stringent limits for a scalar chameleon field, a prominent quintessence dark energy candidate. We find that the coupling constant β is less than 1.9 ×10 7 for n = 1 at 95% confidence level, where n is an input parameter of the self-interaction of the chameleon field ϕ inversely proportional to ϕ n .