A possible NN*(1440) quasi-molecular state

TL;DR

This paper investigates the potential formation of a NN*(1440) quasi-molecular state using a meson exchange model, suggesting it could explain a resonance observed around 2360 MeV.

Contribution

It introduces a meson exchange model to explore the formation of a NN*(1440) quasi-molecular state and links it to experimental resonance observations.

Findings

A NN*(1440) quasi-molecular state with 2-67 MeV binding energy can form.

The observed resonance at 2360 MeV may be a NN*(1440) quasi-molecular state.

The model uses coupling constants from NN scattering and N*(1440) decay data.

Abstract

Inspired by the recent observation of a narrow resonance-like structure around 2360 MeV in the p+n to d + \pi 0 + \pi 0 cross section, the possibility of forming a NN*(1440) quasi-molecular state is investigated by using a meson exchange model in which the \pi, \sigma, \rho\ and \omega\ exchanges in t- and u-channels are considered. By adopting the coupling constants extracted from the relevant NN scattering and N*(1440) decay data, it is found that a deuteron-like quasi-molecular state of NN*(1440) with a binding energy in the range of from 2 to 67MeV can be formed. Therefore, it is speculated that the observed structure around 2360 MeV might be or may have a large component of the NN*(1440) quasi-molecular state.