Resonant behavior of the pp → {pp} s π 0 reaction at the energy s = 2.65 GeV

Abstract

We report on measurements of the differential cross section dσ/dΩ in the energy region of s=2.5–2.9GeV of the reaction pp→{pp}sπ0, where {pp}s is a S01 proton pair. The experiment has been performed with the ANKE spectrometer at COSY-Jülich. The data reveal a peak in the energy dependence of the forward {pp}s differential cross section at the energy s=2.65GeV with the width Γ=0.26GeV, and also the cross section slope changes its sign in the region of the observed peak. This is an indication for the excitation of a new D(2650) resonant state, that may be a dibaryon resonance system consisting of two excited baryons Δ(1232) and N*(1440).