Neutron β Decay: Status and Future of the Asymmetry Measurement

Abstract

With more intense sources of cold and ultracold neutrons becoming available and with improved experimental techniques being developed, determination of |V ud | from neutron β decay with a similar precision to that from from superallowed β decays is within reach. Determination of |V ud | from neutron β decay, free from nuclear corrections, hold the most promise for a further improvement of the determination of |V ud |. The current and future neutron β decay correlation experiments including the UCNA experiment at Los Alamos National Laboratory are reviewed.

Tests of non-standard electroweak couplings of right-handed quarks

“…There exist precise measurements of various angular and spin correlations in the (polarized) neutron β-decay and more experimental results are expected (see e.g. [36]). These are often presented as accurate tests of the chirality of fermion couplings to W .…”

Characterization of thin-foil ultracold neutron detectors

“…Ultracold neutrons (UCNs) are used for a variety of experiments [1], including measurements of the neutron electric dipole moment [2], the neutron lifetime [3][4][5], and the neutron decay beta asymmetry [6][7][8][9]. A key problem for these experiments, however, is detecting the neutrons.…”