Cumulative pion production via successive collisions in nuclear medium

TL;DR

This paper investigates how successive collisions in nuclear media lead to cumulative pion production, emphasizing the role of baryonic resonances and using simulations to analyze the process.

Contribution

It demonstrates that cumulative pion production is primarily driven by baryonic resonances formed during successive collisions, supported by Ultra relativistic Quantum Molecular Dynamics simulations.

Findings

Successive baryonic collisions are key to cumulative pion production.

Resonance mass increases and velocity decreases with each collision.

Simulations confirm the dominance of resonance-nucleon interactions in the process.

Abstract

Production of pions in proton-nucleus (p+A) reactions outside of a kinematical boundary of proton-nucleon collisions, the so-called cumulative effect, is studied. The kinematical restrictions on pions emitted in backward direction in the target rest frame are analyzed. It is shown that cumulative pion production requires a presence of massive baryonic resonances that are produced during successive collisions of projectile with nuclear nucleons. After each successive collision the mass of created resonance may increase and, simultaneously, its longitudinal velocity decreases. Simulations within Ultra relativistic Quantum Molecular Dynamics model reveals that successive collisions of baryonic resonances with nuclear nucleons plays the dominant role in cumulative pion production in p+A reactions.