Role of the N*(1440) resonance in the pp->pnpi+ reaction

TL;DR

This paper investigates the role of the N*(1440) Roper resonance in the pp->pn pi+ reaction, showing its significant contribution at higher energies and emphasizing the dominance of t-channel sigma-meson exchange, based on new experimental data.

Contribution

It introduces the first detailed analysis of the Roper resonance's role in this reaction using an effective Lagrangian approach, aligning theory with recent experimental findings.

Findings

Roper resonance contribution becomes significant above 1.1 GeV

t-channel sigma-meson exchange dominates Roper production

Experimental data supports the resonance's importance at higher energies

Abstract

New measurement by CELSIUS-WASA Collaboration on the pp->pn pi+ reaction reveals clear evidence for the presence of the Roper resonance N*(1440) which has been ignored in previous theoretical calculations. In this article, based on an effective Lagrangian approach and available knowledge on the Roper resonance, we investigate the role of the Roper resonance for the pp->pn pi+ reaction. It is found that the contribution from the Roper resonance N*(1440) becomes significant for kinetic energy above 1.1 GeV, consistent with the new experimental observation. The t-channel sigma-meson exchange is dominant for the production of the Roper resonance.