Total and partial pion absorption cross sections on 4 He in the D resonance region

This paper presents a large solid angle measurement of the positive pion absorption cross section on 4 He and its decomposition into partial channels. The total absorption cross sections at incident pion kinetic energies of Tp1570, 118, 162, and 239 MeV are 3565, 5264, 5165, and 2762 mb, respectively. These values are lower than those reported in some previous experiments. At all pion energies a large fraction of the absorption cross section is due to multinucleon channels. @S0556-2813~98!03108-2#