The induced pseudoscalar coupling and the neutrino helicity from [formula omitted

Abstract

Recent measurements by Roesch et al. of recoil polarizations in 12 C(μ,ν μ) 12 B (g.s.) are analysed when the sign of the helicity h ν of the emitted neutrino is allowed to change. Although the analysis of observables in terms of a ratio of two amplitudes remains the same, the dynamical information on couplings contained in this ratio is different. We conclude, from the experimental results, that the nuclear pseudoscalar coupling is ƒ p =−1.02 if h ν =−1, whereas ƒ p =+2.79 if h ν =+1.