B.M. Barnett

Observation of a new IG(JPC)=1−(0++) resonance at 1450 MeV

Abstract A new IG=1− JPC=0++πη resonance is observed in pp annihilation at rest into π0π0η. It has a mass M=(1450±40)MeV and a width Γ=(270±40)MeV.

The pseudoscalar mixing angle ΘPS from ν and ν′ production in p annihiltion at rest

Abstract We have determined ratios of branching ratios for p p annihilations at rest into π 0 η and π 0 η ′, into ηη and ηη ′, and into ωη and ωη ′. All reactins are observed in two different all-neutral final states. The ratios permit a determination of the pseudoscalar mixing angle. We find Θ PS = −(17.3±1.8)°.

P- versus S-wave pp-annihilation at rest in LH2

Abstract The annihilation p p →π 0 π 0 was measured for antiprotons stopped in liquid hydrogen (LH2). This reaction is only allowed from odd angular momentum states of the p p - atom . The resulting branching ratio BR ( p p →π 0 π 0 ) LH 2 =(6.93±0.22 stat ±0.37 syst )×10 −4 , combined with a previous measurement of the branching ratio BR ( p p →π + π − ) 2 P in gas from the 2P-state of p p 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.

ηη′ threshold enhancement in p̄p annihilations into π0ηη′ at rest

Abstract We report on the observation of an ηη′ threshold enhancement produced in pp annihilations at rest into π0ηη′, which we identify with the recently discovered ƒ 0 (1500) .

Antiproton-proton annihilation at rest into two-body final states

AbstractWe report measurements of branching ratios for production of a series of two meson final states inn

Observation of a scalar resonance decaying to π+π−π0π0 in pp annihilation at rest

bar p

Study of pp annihilation at rest into ωηπ0

np annihilations at rest in liquid hydrogen. We find:n