Upper limit for the cross-section of the overlapping scalar resonances f0(980) and a0(980) produced in proton–proton collisions in the range of the reaction threshold

Abstract

Utilizing a missing mass technique we investigate the pp → ppX reaction scanning beam energies in the range permitting to create a mass close to that of the f0(980) and a0(980) scalar resonances, but still below the K+K− threshold where they decay dominantly into ππ and πη mesons, respectively. Prior to the data analysis we introduce a notion of the close to threshold total cross-section for broad resonances. We estimated for the overlapping mesons a0 and f0 the total cross-section to be smaller than 430 nb at excess energy of Q = 5 MeV. The experiment has been performed at the Cooler Synchrotron (COSY) using the COSY-11 facility.