Speaker
Description
The BRAND experiment is designed to search for hints of physics beyond the Standard Model. This objective is achieved through the precise study of neutron beta decay. Generally, in neutron beta decay, the emitted electron is longitudinally polarized due to the vector and axial couplings inherent in the Weak decay theory. Any deviation from the electron's longitudinal polarization (except electromagnetic corrections) would indicate the presence of new physics. Various correlation coefficients can be constructed from the spin, momentum, and energy of the decay products and the neutron itself. These correlation coefficients exhibit varying sensitivities to scalar and tensor couplings. The 2nd phase of experiment (BRAND-II) will simultaneously measure 11 correlation coefficients: a, A, B, D, H, L, N, R, S, U, and V. Seven of these (H, L, N, R, S, U, V) depend on the transverse polarization of the electron; among these, only N and R have been previously addressed experimentally. The remaining five will be determined for the first time by the BRAND-II experiment. The simultaneous measurement of coefficients a, A, B, and D will help in controlling systematic errors. Furthermore, it will be insightful to extract these coefficients using an experimental technique different from those previously employed.
In this experiment the transverse electron polarization of electrons emitted in the decay of cold neutrons will be measured by leveraging the Mott scattering process. The BRAND-II Mott polarimeter consists of a Multi-wire Drift Chamber (MWDC) to track an electron, and a plastic scintillator to measure the energy of it. A mixture of helium and isobutane will be used in the MWDC at atmospheric pressure. Currently, one segment of the BRAND-II experiment is under construction. The results from the characterization of the BRAND-II Mott polarimeter, such as the 3D position resolution of the MWDC and the energy resolution of the plastic scintillator, will be presented.
