Study of the (3He,t) reaction and the (p,n) reaction at intermediate energies

Within the framework of the Distorted Wave Impulse Approximation (DWIA) a method is presented for the calculation of inelastic and charge exchange scattering processes induced by composite particles. The in those reactions often neglected knockon-exchange contributioins are treated exactly. The basic tool is the multipole expansion method which is repeatedly applied to perform multidimensional integrals involved in both the direct and exchange amplitudes. Based on that method a computer code is developed and is applied to examine the recoil and tensor exchange effects for different multipoles. Neglecting those effects 10-30% error shows up in the calculations. A comparative study of the 90Zr(3He,t)- and 90Zr(p,n)-reactions is then performed at the bombarding energy of 200 MeV per nucleon. It is shown that the (3He,t)-reaction excites the collective 1 hω - (L=1) - and 2 hω - (L=2) - spin-flip modes much more strongly than the (p,n)-reaction. The reason for that is found in the strong surface character of the (3He,t)-reaction. It is proved that both the (p,n)- and (3He,t)-spectra are nearly background free and represent a linear spin-isospin (στ)-response of the target nucleus to the probing (p,n)- and (3He,t)-fields, respectively. (orig./HSI)