Resonances in the System of Pi+Pi- -- Mesons from the Reaction np->npPi+Pi- at Pn=5.20GeV/c: Search, Results of Direct Observations, Interpretation

TL;DR

This paper reports the discovery of ten pi+pi- resonances in np interactions at 5.20 GeV/c, with some identified as sigma0-mesons possibly being glueballs, based on mass spectrum analysis and quantum number estimations.

Contribution

The study identifies multiple pi+pi- resonances, estimates their spins, and suggests some are sigma0-mesons, providing new insights into meson spectroscopy and potential glueball states.

Findings

Ten pi+pi- resonances identified in np interactions.

Resonances at 418, 511, and 757 MeV/c^2 are confirmed as sigma0-mesons.

Some sigma0-mesons may be glueballs.

Abstract

Ten resonances were found in the mass spectrum of pi+pi- -system from the reaction np->nppi+pi- in np-interactions at Pn=5.20 GeV/c in the 1-m HBC of LHE JINR by using the criterion cos(teta)[c.m.c.] p>0. Such effects were not found in pi-pi0 - combinations from the reaction np->pppi-pi0. Therefore, it is necessary to attribute the value of isotopic spin I = 0 to the resonances found in the mass spectrum of the pi+pi- -system. The spin was estimated for the most statistically provided resonances. We determine with a high degree of confidence that J = 0 for the resonances at MR = 757 MeV/c^2 and MR = 418 MeV/c^2. Therefore, it can be affirmed that at least 3 states with quantum numbers of sigma0-meson 0+(0++) have been found at masses of 418, 511 and 757 MeV/c^2. The fact low-mass sigma0-mesons are glueballs is one of the possible interpretations. The comparison with the data of other papers has also been made. The investigation has been performed at the Veksler and Baldin Laboratory of High Energies,JINR.