Multinucleon Short-Range Correlation Model for Nuclear Spectral Functions

TL;DR

This paper develops a relativistic theoretical model for nuclear spectral functions incorporating two- and three-nucleon short-range correlations, crucial for understanding high-energy nuclear processes at major research facilities.

Contribution

It introduces a novel multi-nucleon SRC model based on effective Feynman diagrams, including three-nucleon correlations, using both virtual nucleon and light-front frameworks.

Findings

Derived spectral functions including 2N and 3N SRC contributions.

Developed computational models for SRC spectral functions and momentum distributions.

Provided numerical estimates relevant for high-energy nuclear experiments.

Abstract

The main goal of the research presented in this dissertation was to develop a theoretical model for relativistic nuclear spectral functions at high missing momenta and removal energies based on the multi-nucleon short-range correlation (SRC) model. The nuclear spectral functions are necessary for the description of high energy nuclear processes currently being studied at different labs such as JLAB, LHC and FNAL. The model followed the effective Feynman diagrammatic approach in order to account for the relativistic effects important in the SRC domain. In addition to the two-nucleon (2N) SRC with center of mass motion contribution, the contribution of the three-nucleon SRCs to the spectral functions was also derived. The latter was modeled based on the assumption that the 3N SRCs are a product of two sequential short range nucleon-nucleon (NN) interactions. The nuclear spectral functions models were derived from two theoretical frameworks for evaluating covariant Feynman diagrams: In the first, referred to as the virtual nucleon approximation, the Feynman diagrams were reduced to the time ordered non-covariant diagrams by evaluating the nucleon spectators in the SRC at their positive energy poles, neglecting explicitly the contribution from vacuum diagrams. In the second approach, referred to as the light-front approximation, the boost invariant nuclear spectral function was formulated in the light-front reference frame in which case the vacuum diagrams are kinematically suppressed and the bound nucleon is described by its light-front variables such as momentum fraction, transverse momentum and invariant mass. On the basis of the derived nuclear spectral functions, the corresponding computational models were developed from which the numerical estimates of the SRC spectral functions, the SRC momentum distributions, and the SRC density matrices were obtained.