Eur. Phys. J. A (2013) 49: 59
https://doi.org/10.1140/epja/i2013-13059-x

Regular Article - Theoretical Physics

A possible NN^*(1440) quasi-molecular state

¹ Institute of High Energy Physics, CAS, 100049, Beijing, China
² University of Chinese Academy of Sciences, 100049, Beijing, China
³ College of Physics and Technology, Guangxi Normal University, 541004, Guilin, China
⁴ Theoretical Physics Center for Science Facilities, 100049, Beijing, China
⁵ Physics Department, Hebei University, 071002, Baoding, China
⁶ State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, 100190, Beijing, China

^* e-mail: zhaolu@ihep.ac.cn

Received: 21 February 2013
Revised: 17 April 2013
Accepted: 20 April 2013
Published online: 21 May 2013

Abstract

Inspired by the recent observation of a narrow resonance-like structure around 2360 MeV in the pn → dπ ⁰ π ⁰ cross section, the possibility of forming a NN ^*(1440) quasi-molecular state is investigated by using a meson exchange model in which the π, σ, ρ and ω 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 2 ∼ 67 MeV 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.