Observation of a near-threshold enhancement in the e+e- -->Lambda_c+Lambda_c- cross section using initial-state radiation
Observation of a near-threshold enhancement in the e+e- -->Lambda_c+Lambda_c- cross section using initial-state radiation
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DOI：
10.1103/physrevlett.101.172001
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发表时间：
2008-07
影响因子：
8.6
通讯作者：
G. Pakhlova;I. Adachi;H. Aihara;K. Arinstein;V. Aulchenko;T. Aushev;A. Bakich;V. Balagura
中科院分区：
文献类型：
--
作者：
G. Pakhlova;I. Adachi;H. Aihara;K. Arinstein;V. Aulchenko;T. Aushev;A. Bakich;V. Balagura
我们测量了唯一的e+e-->；Lambda_c+Lambda_c-截面，作为Lambda_c+Lambda_c-阈值附近质心能量的函数。在阈值以上的Lambda_c+Lambda_c不变质量分布中观察到一个显著为8.2 sigma的清晰峰。在对观测到的峰作共振起源的假设下，确定了M=(4634^{+8}_{-7}(stat.)^{+5}_{-8}(sys.))Mev/c2和Gamma_tot=(92^{+40}_{-24}(stat.)}^{+10}_{-21}(sys.))MeV的质量和宽度。这一分析是基于在KEKB非对称能量e+e对撞机上用Belle探测器在Upsilon(4S)共振和附近的连续谱收集的初态辐射光子的事件的研究，其积分光度为695/fb。
We report a measurement of the exclusive e+e- -->Lambda_c+ Lambda_c- cross section as a function of center-of-mass energy near the Lambda_c+ Lambda_c- threshold. A clear peak with a significance of 8.2 sigma is observed in the Lambda_c+ Lambda_c- invariant mass distribution just above threshold. With an assumption of a resonance origin for the observed peak, a mass and width of M=(4634^{+8}_{-7}(stat.)^{+5}_{-8}(sys.))Mev/c2 and Gamma_tot=(92^{+40}_{-24}(stat.)}^{+10}_{-21}(sys.))MeV are determined. The analysis is based on a study of events with initial-state-radiation photons in a data sample collected with the Belle detector at the \Upsilon(4S) resonance and nearby continuum with an integrated luminosity of 695/fb at the KEKB asymmetric-energy e+e- collider.