@article{fa37694fb0214e8ca264422c9f562774,
title = "Improved measurements of two-photon widths of the χcJ states and helicity analysis for χc2 →γγ",
abstract = "Based on 448.1×106 ψ(3686) events collected with the BESIII detector, the decays ψ(3686)→γχcJ,χcJ→γγ(J=0,1,2) are studied. The decay branching fractions of χc0,2→γγ are measured to be B(χc0→γγ)=(1.93±0.08±0.05±0.05)×10-4 and B(χc2→γγ)=(3.10±0.09±0.07±0.11)×10-4, which correspond to two-photon decay widths of Γγγ(χc0)=2.03±0.08±0.06±0.13 keV and Γγγ(χc2)=0.60±0.02±0.01±0.04 keV with a ratio of R=Γγγ(χc2)/Γγγ(χc0)=0.295±0.014±0.007±0.027, where the uncertainties are statistical, systematic and associated with the uncertainties of B(ψ(3686)→γχc0,2) and the total widths Γ(χc0,2), respectively. For the forbidden decay of χc1→γγ, no signal is observed, and an upper limit on the two-photon width is obtained to be Γγγ(χc1)<5.3 eV at the 90% confidence level. The ratio of the two-photon widths between helicity-zero and helicity-Two components in the decay χc2→γγ is also measured to be f0/2=Γγγλ=0(χc2)/Γγγλ=2(χc2)=(0.0±0.6±1.2)×10-2, where the uncertainties are statistical and systematic, respectively.",
keywords = "QUARKONIA, ANNIHILATION, CHROMODYNAMICS, E(+)E(-), BESIII, RATES",
author = "{BESIII Collaboration} and M. Ablikim and Achasov, {M. N.} and S. Ahmed and M. Albrecht and A. Amoroso and An, {F. F.} and Q. An and Bai, {J. Z.} and Y. Bai and O. Bakina and {Baldini Ferroli}, R. and Y. Ban and Bennett, {D. W.} and Bennett, {J. V.} and N. Berger and M. Bertani and D. Bettoni and Bian, {J. M.} and F. Bianchi and E. Boger and I. Boyko and Briere, {R. A.} and H. Cai and X. Cai and O. Cakir and A. Calcaterra and Cao, {G. F.} and Cetin, {S. A.} and J. Chai and Chang, {J. F.} and G. Chelkov and G. Chen and Chen, {H. S.} and Chen, {J. C.} and Chen, {M. L.} and Chen, {S. J.} and Chen, {X. R.} and Chen, {Y. B.} and Chu, {X. K.} and G. Cibinetto and Dai, {H. L.} and Dai, {J. P.} and A. Dbeyssi and D. Dedovich and Deng, {Z. Y.} and A. Denig and I. Denysenko and M. Destefanis and Muchnoi, {N. Yu} and Nikolaev, {I. B.}",
note = "Publisher Copyright: {\textcopyright} 2017 American Physical Society.",
year = "2017",
month = nov,
day = "28",
doi = "10.1103/PhysRevD.96.092007",
language = "English",
volume = "96",
journal = "Physical Review D",
issn = "2470-0010",
publisher = "AMER PHYSICAL SOC",
number = "9",
}