Measurement of the neutrino asymmetry parameter B in neutron decay

Phys Rev Lett. 2007 Nov 9;99(19):191803. doi: 10.1103/PhysRevLett.99.191803. Epub 2007 Nov 8.

Abstract

A new measurement of the neutrino asymmetry parameter B in neutron decay, the angular correlation between neutron spin and antineutrino momentum, is presented. The result, B=0.9802(50), confirms earlier measurements but features considerably smaller corrections. It agrees with the standard model expectation and permits updated tests on "new physics" in neutron decay.