He3(π−,π0) reaction atTπ=200MeV

Energy and angle differential cross sections for the $^{3}\mathrm{He}$(${\ensuremath{\pi}}^{\ensuremath{-}}$,${\ensuremath{\pi}}^{0}$) reaction at ${T}_{\ensuremath{\pi}}=200$ MeV have been measured. Angular distributions for the isobaric analog state and the energy integrated continuum have been obtained from 0\ifmmode^\circ\else\textdegree\fi{} to 90\ifmmode^\circ\else\textdegree\fi{}. The excitation of the analog state seems to be best represented by Glauber model calculations with nuclear wave functions suitable to explain electron scattering, but all model calculations underestimate the forward angles by 1.5 standard errors. The continuum angular distribution has the same shape as the free $p({\ensuremath{\pi}}^{\ensuremath{-}},{\ensuremath{\pi}}^{0})n$ reaction except at forward angles, where the cross section is suppressed by Pauli blocking of the final state. The total isobaric analog state cross section is 6.29\ifmmode\pm\else\textpm\fi{}0.94 mb and the total charge exchange cross section from 0\ifmmode^\circ\else\textdegree\fi{} to 90\ifmmode^\circ\else\textdegree\fi{} is 28.4\ifmmode\pm\else\textpm\fi{}3.8 mb. The latter is one-half the plane wave impulse approximation value.NUCLEAR REACTIONS $^{3}\mathrm{He}$(${\ensuremath{\pi}}^{\ensuremath{-}}$,${\ensuremath{\pi}}^{0}$); ${T}_{{\ensuremath{\pi}}^{\ensuremath{-}}}=200$ MeV; measured $\ensuremath{\sigma}(\ensuremath{\theta})$; $\ensuremath{\theta}=0\ifmmode^\circ\else\textdegree\fi{}\ensuremath{-}90\ifmmode^\circ\else\textdegree\fi{}$; analog state; continuum; compare to theory; deduced effective number of nucleons and Pauli blocking effects.