Two nucleon stripping reactions and the role of the tensor force
Bilhorn, David E.
Doctor of Philosophy
In recent years an increasing number of nuclear reactions have been studied experimentally in which more then one nucleon is transferred from the bombarding particle to the target nucleus. The reactions studied are primarily those in which two nucleons are transferred from an incident three or four nucleon complex, for example (He3,p), (alpha,d), etc. The structure of the angular distributions seem to indicate that at high enough energies "direct" reaction mechanisms may be the predominant reaction process. In section I and II we formulate a plane wave Born Approximation direct reaction treatment of the general stripping reaction based on the work of W. Tobocman. Section III is devoted to reviewing the deuteron induced reactions using this formalism to make clear why tensor force and finite range effects are small in these reactions. The formalism is applied to the two nucleon stripping reaction, specifically the (He3,p) reaction in Chapter IV. To investigate the importance of tensor forces we need to know the properties of the 3-nucleon ground state wave function and of the residual nucleus wave function. A discussion of the 3-nucleon ground state is given in Chapter V and Appendix I. A simple L-S coupling shell model for the residual nucleus is used to give explicit expressions for the cross section in Chapter VI. Finally a discussion of the importance of the tensor force and the ramifications of our formalism are given in Chapter VII, for the reaction He4(He 3,p)Li6.