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Improved measurements of two-photon widths of the χcJ states and helicity analysis for χc2 →γγ. / BESIII Collaboration.
In: Physical Review D, Vol. 96, No. 9, 092007, 28.11.2017.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Improved measurements of two-photon widths of the χcJ states and helicity analysis for χc2 →γγ
AU - BESIII Collaboration
AU - Ablikim, M.
AU - Achasov, M. N.
AU - Ahmed, S.
AU - Albrecht, M.
AU - Amoroso, A.
AU - An, F. F.
AU - An, Q.
AU - Bai, J. Z.
AU - Bai, Y.
AU - Bakina, O.
AU - Baldini Ferroli, R.
AU - Ban, Y.
AU - Bennett, D. W.
AU - Bennett, J. V.
AU - Berger, N.
AU - Bertani, M.
AU - Bettoni, D.
AU - Bian, J. M.
AU - Bianchi, F.
AU - Boger, E.
AU - Boyko, I.
AU - Briere, R. A.
AU - Cai, H.
AU - Cai, X.
AU - Cakir, O.
AU - Calcaterra, A.
AU - Cao, G. F.
AU - Cetin, S. A.
AU - Chai, J.
AU - Chang, J. F.
AU - Chelkov, G.
AU - Chen, G.
AU - Chen, H. S.
AU - Chen, J. C.
AU - Chen, M. L.
AU - Chen, S. J.
AU - Chen, X. R.
AU - Chen, Y. B.
AU - Chu, X. K.
AU - Cibinetto, G.
AU - Dai, H. L.
AU - Dai, J. P.
AU - Dbeyssi, A.
AU - Dedovich, D.
AU - Deng, Z. Y.
AU - Denig, A.
AU - Denysenko, I.
AU - Destefanis, M.
AU - Muchnoi, N. Yu
AU - Nikolaev, I. B.
N1 - Publisher Copyright: © 2017 American Physical Society.
PY - 2017/11/28
Y1 - 2017/11/28
N2 - 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.
AB - 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.
KW - QUARKONIA
KW - ANNIHILATION
KW - CHROMODYNAMICS
KW - E(+)E(-)
KW - BESIII
KW - RATES
UR - http://www.scopus.com/inward/record.url?scp=85037683036&partnerID=8YFLogxK
U2 - 10.1103/PhysRevD.96.092007
DO - 10.1103/PhysRevD.96.092007
M3 - Article
AN - SCOPUS:85037683036
VL - 96
JO - Physical Review D
JF - Physical Review D
SN - 2470-0010
IS - 9
M1 - 092007
ER -
ID: 12670703