Mechanism of Pion Production in $alpha$p Scattering at 1 GeV/nucleon

TL;DR

This study investigates pion production mechanisms in alpha-proton scattering at 4.2 GeV, revealing that inelastic scattering proceeds via Delta and Roper resonance excitations, with detailed decay pathways observed.

Contribution

It provides new experimental insights into the resonance excitation processes and decay channels involved in high-energy alpha-proton scattering.

Findings

Inelastic scattering involves Delta resonance excitation.

Roper resonance excitation contributes to pion production.

Decay channels include nucleon-pion and nucleon-sigma meson systems.

Abstract

The one-pion and two-pion production in the p(alpha, alpha prime)X reaction at an energy of E{alpha} = 4.2 GeV has been studied by simultaneous registration of the scattered alpha particles and the secondary pion or proton. The obtained results demonstrate that the inelastic alpha-particle scattering on the proton at the energy of the experiment proceeds either through excitation and decay of Delta resonance in the projectile or through excitation in the target proton of the Roper resonance, which decays mainly on a nucleon and a pion or a nucleon and a sigma meson - system of two pions in the isospin I = 0, S-wave.