2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/192933A new measurement of the neutrino asymmetry parameter B in neutron decay, the angular correlation between neutron spin and anti-neutrino momentum, is presented. The result, B=0.9802(50), agrees with the Standard Model expectation and earlier measurements, and permits improved tests on ``new physics'' in neutron decay.4 pages, 2 figures; v2: revised PRL versionHigh Energy Physics - Phenomenologytext