Experimental study of the inclusive η-spectrum from p $$\bar p$$ annihilations at rest in liquid hydrogen.

The inclusive η-momentum spectrum from $$\bar p$$ annihilations at rest in liquid hydrogen was measured at LEAR. Branching ratios were obtained for, and ηη(8.1±3.1)×10. An upper limit for $$p\bar p \to \eta \eta '$$ of 1.8×10 at 95% CL was found. The ratio of the branching ratios is BR(ηϱ)/BR(ηω)=0.51. For the ratio of branching ratios into two pseudoscalar mesons, we have BR( ηπ)/BR(ππ)=0.65±0.14, BR( ηη)/BR(ππ), BR( η η)/BR(ππ) at 95% CL, and BR( ηη)/BR( ηπ). [ABSTRACT FROM AUTHOR]