The pp→ppπ+π- and pp→ppπ0π0 reactions have been measured at CELSIUS in the energy range Tp=775-1360 MeV using the WASA 4π detector. For Tp<1 GeV the data are in accordance with Roper excitation and σ correlations in the ππ system, respectively. For Tp>1 GeV they agree with ΔΔ excitation in the special configuration (ΔΔ)0+. For the π0π0 channel an enhancement at low Mπ0π0 masses is observed, which possibly points to Bose-Einstein correlations.
Bose-Einstein correlations of neutral gauge bosons in pp collisions