Determination of the Weak Axial Vector Coupling λ=g_{A}/g_{V} from a Measurement of the β-Asymmetry Parameter A in Neutron Beta Decay

Mund, D.D.MundMärkisch, B.B.MärkischDeissenroth, M.M.DeissenrothKrempel, J.J.KrempelSchumann, MarcMarcSchumann0000-0002-5036-1256Abele, H.H.AbelePetoukhov, A.A.PetoukhovSoldner, T.T.Soldner2024-10-152024-10-152013-04https://boris-portal.unibe.ch/handle/20.500.12422/119714We report on a new measurement of the neutron beta-asymmetry parameter A with the instrument \perkeo. Main advancements are the high neutron polarization of P=99.7(1) from a novel arrangement of super mirror polarizers and reduced background from improvements in beam line and shielding. Leading corrections were thus reduced by a factor of 4, pushing them below the level of statistical error and resulting in a significant reduction of systematic uncertainty compared to our previous experiments. From the result A0=−0.11996(58), we derive the ratio of the axial-vector to the vector coupling constant λ=gA/gV=−1.2767(16)en500 - Science::530 - PhysicsDetermination of the Weak Axial Vector Coupling λ=g_{A}/g_{V} from a Measurement of the β-Asymmetry Parameter A in Neutron Beta Decayarticle10.7892/boris.493141204.0013v110.1103/PhysRevLett.110.172502