Münster 2017 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 24: Fundamental Symmetries I

HK 24.1: Group Report

Tuesday, March 28, 2017, 14:00–14:30, F 073

Precision Measurement of the Beta Asymmetry in Neutron Beta Decay with Perkeo III — •Heiko Saul^1,2, Hartmut Abele², Dirk Dubbers³, Bastian Märkisch¹, Alexandr Pethukov⁴, Christoph Roick¹, Ulrich Schmidt³, Torsten Soldner⁴, Xiangzun Wang², and Dominik Werder³ — ¹Physik Department, TU München — ²Atominstitut, TU Wien — ³Physikalisches Institut, Universität Heidelberg — ⁴Institut Laue-Langevin, Grenoble

Neutron beta decay is described accurately within the standard model of particle physics using the first CKM-matrix element, V_ud, and the ratio of vector and axial vector couplings, λ, as parameters. Angular correlations, spectra and the neutron lifetime are accessible experimentally, providing an excellent toolkit for investigating the structure of weak interaction.

Measuring the Beta Asymmetry, A, is the most precise way of determining λ, which is an important standard model parameter and necessary for the determination of V_ud from Neutron Decay. Moreover it allows to derive limits on non-standard model couplings by combining with measurements of other correlation coefficients.

In this talk we present the most precise measurement of the Beta Asymmetry performed with the decay spectrometer Perkeo III carried out at the PF1B cold neutron beam facility at the Institut Laue-Langevin. We discuss the result and its implications.