Polarization transfer measurements for the13C(p→,n→)13Nreaction at 197 MeV and empirical isovector spin-longitudinal response for the(1/2)g.s.−→(1/2)1+transition

Abstract

We present differential cross sections and complete sets of polarization-transfer coefficients, ${D}_{\mathrm{ij}},$ obtained in the ${}^{13}\mathrm{C}(\stackrel{\ensuremath{\rightarrow}}{p},\stackrel{\ensuremath{\rightarrow}}{n}{)}^{13}\mathrm{N}$ reaction studied at 197 MeV incident proton energy and laboratory angles between $0\ifmmode^\circ\else\textdegree\fi{}$ and $33\ifmmode^\circ\else\textdegree\fi{}.$ These complete sets of polarization observables are used to obtain spin-longitudinal and spin-transverse components for transitions to the ground state, to the first, and to the unresolved second and third excited states in ${}^{13}\mathrm{N}$ at 2.36 MeV and $(3.50+3.55) \mathrm{MeV},$ respectively. The results are used to obtain the two $\ensuremath{\Delta}{J}^{\ensuremath{\pi}}$ contributions for the ground and first excited state transitions and are compared with corresponding distorted-wave impulse approximation (DWIA) calculations. In particular, empirical angular distribution values for the unique spin-longitudinal $\ensuremath{\Delta}{J=0}^{\ensuremath{-}}$ transition to the first excited state in ${}^{13}\mathrm{N}$ are obtained and compared with DWIA calculations.