The inclusive η-momentum spectrum from {Mathematical expression} annihilations at rest in liquid hydrogen was measured at LEAR. Branching ratios were obtained for {Mathematical expression}, and ηη(8.1±3.1)×10 -5. An upper limit for {Mathematical expression} of 1.8×10 -4 at 95% CL was found. The ratio of the branching ratios is BR(ηρ{variant})/BR(ηω)=0.51 -0.06 +0.20. For the ratio of branching ratios into two pseudoscalar mesons, we have BR(ηπ 0)/BR(π 0π 0)=0.65±0.14, BR(ηη)/BR(π 0π 0), BR(ηη ′)/BR(π 0π 0) at 95% CL, and BR(ηη)/BR(ηπ 0). © 1989 Springer-Verlag.
Source: Scopus