Abstract
We present a precision measurement of the axial-vector coupling constant in the decay of polarized free neutrons. For the first time, a pulsed cold neutron beam was used for this purpose. By this method, leading sources of systematic uncertainty are suppressed. From the electron spectra we obtain , which confirms recent measurements with improved precision. This corresponds to a value of the parity violating beta asymmetry parameter of . We discuss implications on the Cabibbo-Kobayashi-Maskawa matrix element and derive a limit on left-handed tensor interaction.
- Received 31 January 2019
DOI:https://doi.org/10.1103/PhysRevLett.122.242501
© 2019 American Physical Society