Universality of Short-Range Correlations in One- and Two-Nucleon Momentum Distributions of Nuclei

TL;DR

This paper demonstrates the universal features of short-range correlations in nuclear momentum distributions across various nuclei, showing that high-momentum behaviors are consistent and can be modeled by two-nucleon correlation frameworks.

Contribution

It provides a comprehensive analysis of one- and two-body momentum distributions in nuclei, confirming the universal nature of short-range correlations and their relation to deuteron-like structures.

Findings

High-momentum parts of one-body distributions are similar across nuclei.

Two-nucleon momentum distributions exhibit universal behavior predicted by models.

Deuteron-like spin-isospin contributions scale to deuteron distributions.

Abstract

Universality of short range correlations has been investigated both in coordinate and in momentum space, by means of one-and two-body densities and momentum distributions. In this contribution we discuss one- and two-body momentum distributions across a wide range of nuclei and their common features which can be ascribed to the presence of short range correlations. Calculations for few-body nuclei, namely 3He and 4He, have been performed using exact wave functions obtained with Argonne nucleon-nucleon interactions, while the linked cluster expansion technique is used for medium-heavy nuclei. The center of mass motion of a nucleon-nucleon pair in the nucleus, embedded in the full two-body momentum distribution n_NN(krel,KCM), is shown to exhibit the universal behavior predicted by the two-nucleon correlation model, in which the nucleon-nucleon pair moves inside the nucleus as a deuteron in a mean-field. Moreover, the deuteron-like spin-isospin (ST)=(10) contribution to the pn two-body momentum distribution is obtained, and shown to exactly scale to the deuteron momentum distribution. Universality of correlations in two-body distributions is cast onto the one-body distribution n(k1), obtained by integration of the two-body n_NN(k1, k2): in particular, the high momentum part of n(k1) exhibits the same pattern for all considered nuclei, in favor of a universal character of the short range structure of the nuclear wave function. Perspectives of this work, namely the calculation of reactions involving light and complex nuclei with realistic wave functions and effects of Final State Interactions (FSI), investigated by means of distorted momentum distributions within the Glauber multiple scattering approach, are eventually discussed.