Search for an Isospin I =3 Dibaryon

Abstract

Various theoretical calculations based on QCD or hadronic interactions predict that in addition to the recently observed dibaryon resonance $d^{\ast }(2380)$ with $I(J^P)=0(3^{+})$ there should also exist a dibaryon resonance with mirrored quantum numbers $I(J^P)=3(0^{+})$. We report here on a search for such a $NN$-decoupled state in data on the $pp\to pp\ddot{I}{€}^{+}\ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^{-}$ reaction. Since no clear-cut evidence has been found, we give upper limits for the production cross section of such a resonance in the mass range 2280 - 2500 MeV.