Experimental study of the inclusive η-spectrum from proton-antiproton annihilations at rest in liquid hydrogen

The inclusive I·-momentum spectrum from Mathematical expression annihilations at rest in liquid hydrogen was measured at LEAR. Branching ratios were obtained for Mathematical expression, and I·I·(8.1±3.1)A—10-5. An upper limit for Mathematical expression of 1.8A—10-4 at 95% CL was found. The ratio of the branching ratios is BR(I·Ivariant)/BR(I·I‰)=0.51-0.06+0.20. For the ratio of branching ratios into two pseudoscalar mesons, we have BR(I·I€0)/BR(I€0I€0)=0.65±0.14, BR(I·I·)/BR(I€0I€0), BR(I·I·â€²)/BR(I€0I€0) at 95% CL, and BR(I·I·)/BR(I·I€0). © 1989 Springer-Verlag.