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arXiv · 1204.0013

Determination of the Weak Axial Vector Coupling from a Measurement of the Beta-Asymmetry Parameter A in Neutron Beta Decay

D. Mund·B. Maerkisch·M. Deissenroth·J. Krempel·M. Schumann·H. Abele·A. Petoukhov·T. Soldner
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Abstract

We 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 $A_0 = -0.11996(58)$, we derive the ratio of the axial-vector to the vector coupling constant $\lambda = g_\mathrm{A}/g_\mathrm{V} = -1.2767(16)$

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D. Mund, B. Maerkisch, M. Deissenroth, J. Krempel, M. Schumann, H. Abele, A. Petoukhov, T. Soldner. 2012-03-30. Determination of the Weak Axial Vector Coupling from a Measurement of the Beta-Asymmetry Parameter A in Neutron Beta Decay. https://doi.org/10.1103/physrevlett.110.172502

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