Pion production off the nucleon
  We have studied charged current neutrino/antineutrino induced weak pion production from nucleon. For the present study, contributions from $\Delta(1232)$-resonant term, non-resonant background terms as well as contribution from higher resonances viz. $P_{11}$(1440), $D_{13}$(1520), $S_{11}$(1535), $S_{11}$(1650) and $P_{13}$(1720) are taken. To write the hadronic current for the non-resonant background terms, a microscopic approach based on SU(2) non-linear sigma model has been used. The vector form factors for the resonances are obtained from the helicity amplitudes provided by MAID. Axial coupling in the case of $\Delta(1232)$ resonance is obtained by fitting the ANL and BNL $\nu$-deuteron reanalyzed scattering data. The results of the cross sections are presented and discussed for all the possible channels of single pion production induced by charged current interaction. 
M. Rafi Alam, M. Sajjad Athar, Shikha Chauhan and S. K. Singh
hep-ph