Probing of compact baryonic configurations in nuclei in $A(p,{\bar p})X$ reactions and antiproton formation length in nuclear matter

TL;DR

This study investigates antiproton production in proton-nucleus collisions, revealing evidence for compact baryonic configurations and estimating the antiproton formation length in nuclear matter to be around 4.5 fm.

Contribution

It provides experimental evidence for compact baryon configurations in nuclei and estimates the antiproton formation length in nuclear matter, advancing understanding of hadronization in nuclear environments.

Findings

Antiproton cross section ratios show three plateaus indicating compact baryon configurations.

Weak antiproton absorption in nuclei suggested by cross section ratio comparisons.

Antiproton formation length in nuclear matter estimated at approximately 4.5 fm.

Abstract

Inclusive cross sections $\sigma^A=Ed^3{\sigma(X,P_t^2)/d^3p}$ of antiproton and negative pion production on Be, Al, Cu and Ta targets hit by 10 GeV protons were measured at the laboratory angles of 10.5$^{\circ}$ and 59$^{\circ}$. Antiproton cross sections were obtained in both kinematically allowed and kinematically forbidden regions for antiproton production on a free nucleon. The antiproton cross section ratio as a function of the longitudinal variable $X$ exhibits three separate plateaus which gives evidence for the existence of compact baryon configurations in nuclei-small-distance scaled objects of nuclear structure. Comparability of the measured cross section ratios with those obtained in the inclusive electron scattering off nuclei suggests a weak antiproton absorption in nuclei. Observed behavior of the cross section ratios is interpreted in the framework of a model considering the hadron production as a fragmentation of quarks (antiquarks) into hadrons. It has been established that the antiproton formation length in nuclear matter can reach the magnitude of 4.5 fm.