Speaker
Description
Exotic, BSM components of the weak interaction will be probed in the BRAND
experiment via measurement of correlation coefficients of neutron β-decay.
Ultimately, the BRAND detection setup will be able to provide precisely measured
eleven correlation coefficients (a, A, B, D, H, L, N, R, S, U, V). Among them, seven (H,
L, N, R, S, U, V) are dependent on the transverse electron polarization, which
vanishes in the Standard Model. Coefficients H, L, S, U and V were never measured
before.
Both electrons and protons from β-decay of polarized, free neutrons will be
registered in the detection system, permitting the determination of complete
kinematics of the decay. Electrons’ energy, momentum and transverse spin
component are measured in the Mott polarimeter which consists of the Multi-Wire
Drift Chamber, a set of scintillation detectors and the Mott scattering target. The
electron detection setup is optimized for the low-energy β-particles. The detection of
low-energy protons from the β-decay is realized with a system that involves the
acceleration and subsequent conversion of protons into bunches of secondary
electrons.
In this contribution, results of the first pilot run of the BRAND experiment performed
in September-October 2021 at the polarized, cold neutron beam facility PF1B at the
Laue-Langevin Institute (ILL) in Grenoble, France will be reported. The emphasis will
be put on the description and the performance of the electron detection system.
