Isospin Constraints on Semi-inclusive Neutrino Reactions and Their Hadronic Analogs

Abstract

The processes $\nu \left(\overline{\nu }\right)+\mathrm{target}\to \mathrm{hadron}+\mu \left(\overline{\mu }\right)+\mathrm{anything}$ are considered in the cases where the hadron selected has $I=\frac{1}{2} or 1$. Inequalities are given which follow from the conventional assignment of isospin to the weak current (for $\Delta S=0, 1$) and the charge-symmetry conditions for the $\Delta S=0\mathrm{}$ current. $\nu d$ and $\overline{\nu }d$ processes with $\Delta S=1\mathrm{}$ yield an equality if the hadron selected has $I=1\mathrm{}$. The hadronic analogs of these reactions are also discussed; bounds are given for ${\pi }^{-}+p\to \mathrm{hadron}+\mathrm{anything}$, which are stronger than those previously reported.