Improved measurements of two-photon widths of the chi(cJ) states and helicity analysis for chi(c2) -> gamma gamma

doi:10.1103/PhysRevD.96.092007

	Improved measurements of two-photon widths of the chi(cJ) states and helicity analysis for chi(c2) -> gamma gamma
	BESIII Collaboration
刊名	PHYSICAL REVIEW D
	2017
卷号	96 期号:9 页码:92007
ISSN号	2470-0010
DOI	10.1103/PhysRevD.96.092007
文献子类	Article
英文摘要	Based on 448.1 x 10(6) Psi(3686) events collected with the BESIII detector, the decays Psi(3686) -> gamma chi(cJ), chi(cJ) -> gamma gamma(J = 0, 1, 2) are studied. The decay branching fractions of chi(c0,2) -> gamma gamma are measured to be B(chi(c0) -> gamma gamma) = (1.93 +/- 0.08 +/- 0.05 +/- 0.05) x 10(-4) and B(chi(c2) -> gamma gamma) = (3.10 +/- 0.09 +/- 0.07 +/- 0.11) x 10(-4) which correspond to two-photon decay widths of Gamma(gamma gamma)(chi(c0)) = 2.03 +/- 0.08 +/- 0.06 +/- 0.13 keV and Gamma(gamma gamma)(chi(c2)) = 0.60 +/- 0.02 +/- 0.01 +/- 0.04 keV with a ratio of R = Gamma(gamma gamma)(chi(c2))/Gamma(gamma gamma)(chi(c0)) = 0.295 +/- 0.014 +/- 0.007 +/- 0.027, where the uncertainties are statistical, systematic and associated with the uncertainties of B(Psi(3686) -> gamma chi(c0,2)) and the total widths Gamma(chi(c0,2)), respectively. For the forbidden decay of chi(c1) -> gamma gamma, no signal is observed, and an upper limit on the two-photon width is obtained to be Gamma(gamma gamma)(chi(c1)) < 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 chi(c2) -> gamma gamma is also measured to be f(0/2) = Gamma(lambda=0)(gamma gamma) (chi(c2))/Gamma(lambda=2)(gamma gamma) (chi(c2)) = (0.0 +/- 0.6 +/- 1.2) x 10(-2), where the uncertainties are statistical and systematic, respectively.
电子版国际标准刊号	2470-0029
WOS关键词	QUARKONIA ; ANNIHILATION ; CHROMODYNAMICS ; E(+)E(-) ; BESIII ; RATES
WOS研究方向	Astronomy & Astrophysics ; Physics
语种	英语
WOS记录号	WOS:000416315000002
内容类型	期刊论文
源URL	[http://ir.ihep.ac.cn/handle/311005/284664]
专题	高能物理研究所_实验物理中心
作者单位	中国科学院高能物理研究所
推荐引用方式 GB/T 7714	BESIII Collaboration. Improved measurements of two-photon widths of the chi(cJ) states and helicity analysis for chi(c2) -> gamma gamma[J]. PHYSICAL REVIEW D,2017,96(9):92007.
APA	BESIII Collaboration.(2017).Improved measurements of two-photon widths of the chi(cJ) states and helicity analysis for chi(c2) -> gamma gamma.PHYSICAL REVIEW D,96(9),92007.
MLA	BESIII Collaboration."Improved measurements of two-photon widths of the chi(cJ) states and helicity analysis for chi(c2) -> gamma gamma".PHYSICAL REVIEW D 96.9(2017):92007.