Neutron-proton final state interaction in the 3H(3He,pα)n reaction at low bombarding energies

The ³H(³He, pα)n reaction has been studied in a kinematically complete experiment at ³He bombarding energies between 0.31 and 2.80 MeV in order to detect a possible resonant energy dependence of the spin singlet (T = 1) neutron-proton final state interaction (FSI). The data in the region of low n-p relative energies have been analyzed in terms of the Watson-Migdal formalism. Only a slight relative increase of the ¹S₀ n-p FSI is observed with increasing bombarding energy. This result is not easily related to the strong isospin violations found in the two-body reaction ³H(³He, d)⁴He at similar ³He energies.