Neutron beta decay and the right-handed current problem

The renormalization of the axial-vector coupling constant, λ=gA/gV, extracted from the neutron lifeime (λτ) and from the neutron beta decay asymmetry (λc) is considered carefully in the standard model of the electroweak interaction λτ should be equal to λc. According to recent experimental data on neutron beta decay, λτ and λc seem to differ from each other. This fact is explained in the framework of the manifestly left-right symmetric model SU(2)LxSU(2)RxU(1). The possibility of the existence of the right-handed current in the neutron beta decay is pointed out. A joint analysis of neutron beta decay and muon decay is performed, the right-handed current parameters are estimated. The axial-vector constant renormalization (λN) by right-handed currents is evaluated. (orig.)D