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Belle实验上发现新的矢量粒子

Observation of new resonant structures at Belle

  • 摘要: Belle实验在Υ(4S)共振态及其附近采集了大量数据,利用初态辐射(ISR)的方法,测量了e+e-→π+π-J/ψ,π+π-ψ(2S)和K+K-J/ψ等过程从阈值到5.5 GeV间的产生截面.证实了BaBar合作组发现的Y(4260)和Y(4360)的存在,并更新了其共振参数,同时发现了Y(4008)和Y(4660)两个共振结构.以上观测与已知的粲偶素粒子性质不同,可能是新的粲偶素态,也可能是粲偶素混杂态,或者由其他未知的动力学原因造成.

     

    Abstract: The cross sections for three initial-state radiation processes, e+e-→π+π-J/ψ, π+π-ψ(2S), and K+K-J/ψ have been measured between threshold and s= 5.5 GeV, using data on and off the Υ(4S) resonance collected with the Belle detector at KEKB. The Y(4260) and Y(4360) observed by the BaBar collaboration are confirmed, and the resonance parameters improved. Two new resonant structures, the Y(4008) and Y(4660) have been observed for the first time. There are no known vector charmonium states that match these new observations, which must be either new charmonium states or charmonium hybrids, or are produced via other dynamics.

     

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