Probing the Structure of Deuteron at Very Short Distances

Abstract

We study the electrodisintegration of deuteron at quasi-elastic kinematics and high transferred momentum as a probe for the short distance structure in nuclei. In this reaction, an electron hits a nucleus of deuterium, which breaks up into a proton-neutron pair. We focus our attention on events where fast nucleons emerge, corresponding to nuclear configurations where the bound nucleons have a high relative momentum (exceeding 700 MeV/c). The present research is relevant to physical systems where high-density nuclear matter is present. This condition covers a wide range of physics, from neutron stars to nuclei stability and the repulsive nuclear core. The present work differs from previous studies in two crucial features. One is the definition of the deuteron wave function, which include terms of a relativistic origin that can be ordered based on their relative contribution to the deuteron's internal momentum distribution. These terms, related to the off-shell properties of the nucleon-nucleon bound-state, do not occur in non-relativistic quantum mechanics. However, they become increasingly important in describing configurations with a high nucleon-nucleon relative momentum. The second difference is that we account for the off-shell nature of the bound nucleon that enters on the definition of the (half-off-shell) electromagnetic current. We avoid many of the difficulties inherent to the relativistic nature of the processes involved by adopting a theoretical framework known as Light Front dynamics. Simultaneous simplifications in the definition of the relativistic wave function for the proton-neutron bound state and the treatment of the (half-off-shell) electromagnetic current for the bound nucleon are among the essential advantages resulting from the use of the Light Front dynamics.