JP= 0−, T= 0 and mass 2065 MeV could be the origin of the narrow peak in the (π+, π−)
double charge exchange cross-sections on nuclei. We investigate the six-quark system with
these quantum-numbers within the constituent quark model, with linear confinement,
effective one-gluon exchange at short range and chiral interactions between quarks (π-and
σ-exchange). We classify all possible six quark states with JP= 0−, T= 0, and with N= 1 and 3 …