Measurement of the invariant-mass spectrum for the two photons from the eta --> pi0 gamma gamma decay

Jul, 2008

Citations per year

2009201320172021202402468
Abstract: (APS)
New results on the rare, doubly radiative decay η→π0γγ have been obtained from a revised analysis of the Crystal Ball experiment performed at the AGS. The analysis yields the first information on the dependence of the decay width, Γ(η→π0γγ), on the two-photon invariant mass squared, m2(γγ). A re-evaluation of the branching ratio is also made, BR(η→π0γγ)=(2.21±0.24stat±0.47syst)×10−4; it implies that the decay width is Γ(η→π0γγ)=0.285±0.031stat±0.061syst eV. These results are close to predictions based on chiral perturbation theory with vector-meson dominance.
  • 13.20.-v
  • 12.39.Fe
  • 14.40.Aq
  • pi- p: exclusive reaction
  • eta: rare decay
  • mass spectrum: two-photon
  • eta: width
  • eta: branching ratio
  • perturbation theory: chiral
  • vector dominance