Speaker
Description
Understanding the polarization of final-state leptons in neutrino–nucleus
interactions plays a significant role in probing fundamental symmetries. We present
an implementation of final-state lepton polarization within the GENIE neutrino
event generator, focusing on charged-current quasielastic (CCQE) and
two-particle–two-hole (2p2h) scattering processes. The polarization vector of the
outgoing lepton is calculated using a covariant formalism based on the polarization
density matrix derived from the leptonic and nuclear tensors. The polarization
information is integrated into GENIE’s event record, enabling subsequent analysis
and detector response studies sensitive to spin-dependent effects. Validation was
performed for all CCQE and 2p2h models currently implemented in GENIE. This
development enables detailed studies of polarization-sensitive observables,
including lepton angular asymmetries and potential non-standard interactions
signatures in neutrino scattering. It enhances the realism of GENIE simulations
and provides a tool for more complete modeling of polarization-dependent
observables in neutrino experiments such as DUNE and Hyper-Kamiokande.
