The annihilation pp→π0π0 was measured for antiprotons stopped in liquid hydrogen (LH2). This reaction is only allowed from odd angular momentum states of the pp-atom. The resulting branching ratio BR(pp→π0π0)LH2=(6 .93±0.22stat±0.37syst)×10 -4, combined with a previous measurement of the branching ratio BR(pp→π+π-)2P in gas from the 2P-state of pp suggests a fraction of P-wave annihilation in LH2 of (28.8±3.5)%, much larger than the values obtained from other annihilation channels. A method of reconciling the contradictory results is discussed.
ASJC Scopus subject areas
- Nuclear and High Energy Physics