Resonance structure in the γγ and ${\pi }^0{\pi }^0$ systems in dC interactions

Abstract

Along with ${\pi }^0$ and η mesons, a resonance structure in the invariant mass spectrum of two photons at Mγγ = 360 \pm 7 \pm 9 MeV is observed in the reaction d + C \rightarrow γ + γ + X at momentum 2.75 GeV/c per nucleon. Estimates of its width and production cross section are Γ = 64 \pm 18 MeV and ${\sigma }_{\gamma \gamma }$ = 98 \pm 24 μb, respectively. The collected statistics amount to 2339 \pm 340 events of 1.5 \cdot 10^6 triggered interactions of a total number ~ 10^12 of dC-interactions. The results on observation of the resonance in the invariant mass spectra of two ${\pi }^0$ mesons are presented: the data obtained in the d + C \rightarrow γ + γ reaction is confirmed by the d + C \rightarrow ${\pi }^0$ + ${\pi }^0$ reaction: $M_{{\pi }^0{\pi }^0}$ = 359.2 \pm 1.9 MeV, Γ = 48.9 \pm 4.9 MeV; the ratio of Br(R\rightarrowγγ) / Br(R\rightarrow${\pi }^0{\pi }^0$) = (1.8 ÷ 3.7)\cdot10^-3.

10 pages, 11 figures

References in corpus (2)

• Resonance Structure in the $\gamma \gamma$ Invariant Mass Spectrum in $p$C- and $d$C-Interactions
• Observation of New Resonance Structure in the Invariant Mass Spectrum of Two gamma-Quanta in dC-Interactions at Momentum 2.75 GeV/c per Nucleon