Hyperon polarization in u_mu charged current interaction at the NOMAD energies

We show that, in $ u_mu Nto mu^-Lambda X$ at the NOMAD energies, it is impossible to separate the products of the fragmentation of the struck quark from those of the nucleon remnant. The latter has a large contribution even in the current fragmentation region and has to be taken into account in calculating $Lambda$ polarization using different pictures. Based on this, we make a rough estimation for the longitudinal $Lambda$ polarization in $ u_{mu} N to mu^- Lambda X$ at the NOMAD energies. A comparison with the data is given and predictions for $ u_mu Ntomu^-Sigma^+X$ are presented.