Publikace na Matematicko-fyzikální fakulta |
2023
Abstrakt
We report the measurement of the two-photon decay width of chi c2(1P) in two-photon processes at the Belle experiment. We analyze the process gamma gamma ->chi c2(1P)-> J/psi gamma, J/psi -> l(+)l(-) (l=e or mu) using a data sample of 971 fb(-1) collected with the Belle detector at the KEKB e(+)e(-) collider.
In this analysis, the product of the two-photon decay width of chi c2(1P) and the branching fraction is determined to be gamma gamma gamma(chi c2(1P))B(chi c2(1P)-> J/psi gamma)B(J/psi -> l(+)l(-))=14.8 +/- 0.3(stat.) +/- 0.7(syst.) eV, which corresponds to gamma gamma gamma(chi c2(1P)) = 653 +/- 13(stat.) +/- 31(syst.) +/- 17(B.R.) eV, where the third uncertainty is from B(chi c2(1P)-> J/psi gamma) and B(J/psi -> l(+)l(-)).