ISOSPIN SYMMETRY BREAKING AND BRANCHING RATIO IN THE DEUTERON REACTIONS AT VERY LOW ENERGIES

Abstract

The target-material dependence of the neutron-proton branching ratio and breaking of the isospin symmetry in the the 2H(d, n)3He and 2H(d, p)3H reactions at very low deuteron energies have been investigated. Angular distributions and total cross sections of the proton and neutron mirror channels have been measured for nuclear reactions taking place in different metallic environments. For Sr , Li , Na targets, we have found a first evidence for an alteration of the neutron-proton branching ratio and angular anisotropy of the neutron channel. We discuss various theoretical approaches explaining isospin mixing effects both in gas and metallic target experiments including a deuteron polarization in the crystal lattice. Direct reaction contribution has been calculated within the zero range distorted wave Born approximation (DWBA).