Quasielastic production of polarized hyperons in antineutrino--nucleon reactions

Abstract

We have studied the differential cross section as well as the longitudinal and perpendicular components of polarization of final hyperon($\Lambda$,$\Sigma$) produced in the antineutrino induced quasielastic charged current reactions on nucleon and nuclear targets. The nucleon-hyperon transition form factors are determined from the experimental data on quasielastic $(\Delta S =0)$ charged current (anti)neutrino--nucleon scattering and the semileptonic decay of neutron and hyperons assuming G--invariance, T--invariance and SU(3) symmetry. The vector transition form factors are obtained in terms of nucleon electromagnetic form factors for which various parameterizations available in literature have been used. A dipole parameterization for the axial vector form factor and the pseudoscalar transition form factor derived in terms of axial vector form factor assuming PCAC and GT relation extended to strangeness sector have been used in numerical evaluations. The flux averaged cross section and polarization observables corresponding to CERN Gargamelle experiment have been calculated for quasielastic hyperon production and found to be in reasonable agreement with the experimental observations. The numerical results for the flux averaged differential cross section$\frac{d\sigma}{dQ^2}$ and longitudinal(perpendicular) polarization $P_L(Q^2)(P_P(Q^2))$ relevant for the antineutrino fluxes of MINER$\nu$A, MicroBooNE, and T2K experiments have been presented. This will be useful in interpreting future experimental results on production cross sections and polarization observables from the experiments on the quasielastic production of hyperons induced by antineutrinos and explore the possibility of determining the axial vector and pseudoscalar form factors in the strangeness sector.