Quantifying short-range correlations in nuclei

TL;DR

This paper introduces a method to quantify short-range correlations in nuclei by counting nucleon pairs and triples with specific quantum numbers, revealing their mass dependence and relation to nuclear phenomena like the EMC effect.

Contribution

It proposes a novel approach to quantify 2N and 3N SRC in nuclei based on counting nucleon pairs and triples with zero relative orbital momentum, linking SRC to local nuclear dynamics.

Findings

Proton-neutron 2N SRC outnumber proton-proton and neutron-neutron SRC.

The probability of SRC has a soft dependence on mass number A.

A linear relationship between the EMC effect and proton-neutron SRC pairs is observed.

Abstract

An approximate method to quantify the magnitude of the two-nucleon (2N) and three-nucleon (3N) short-range correlations (SRC) and their mass dependence is proposed. The proposed method relies on the concept of the "universality" or "local nuclear character" of the SRC. We quantify the SRC by computing the number of independent-particle model (IPM) nucleon pairs and triples which reveal beyond-mean-field behavior. It is argued that those can be identified by counting the number of nucleon pairs and triples in a zero relative orbital momentum state. A method to determine the quantum numbers of pairs and triples in an arbitrary mean-field basis is outlined. The mass dependence of the 2N and 3N SRC is studied. The predictions are compared to measurements. This includes the ratio of the inclusive inelastic electron scattering cross sections of nuclei to 2H and 3He at large values of the Bjorken variable. Corrections stemming from the center-of-mass motion of the pairs are estimated. We find that the relative probability per nucleon for 2N and 3N SRC has a soft dependence with mass number A and that the proton-neutron 2N SRC outnumber the proton-proton (neutron-neutron) 2N SRC. A linear relationship between the magnitude of the EMC effect and the predicted number of proton-neutron SRC pairs is observed. This provides support for the role of local nuclear dynamics on the EMC effect.