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

Zhen Ouyang, Ju-Jun Xie, Bing-Song Zou, Hu-Shan Xu

Published 2008-08-25, updated 2009-02-25Version 3

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.