Phenomenology of light hadrons in a chiral effective theory

We present the results of a recent calculation of the pion production cross section as might be determined in proposed Jefferson Lab measurements involving spectator tagging in single-inclusive proton electroproduction on a fixed neutron target. Estimates are computed assuming the Sullivan process as the dominant mechanism, and chiral effective Lagrangians provide a description of the relevant hadronic interactions. We also assess the role of the $\Delta$ isobar in generating the light quark sea asymmetry using $\chi$-PT.