Observation of a Charged Charmoniumlike Structure Zc (4020) and Search for the Zc (3900) in e+e- → π+ π-hc
Observation of a Charged Charmoniumlike Structure Zc (4020) and Search for the Zc (3900) in e+e- → π+ π-hc
复制标题
带电Charmonium类结构Z(c) (4020)的观察和在e( )e(-) -> pi( ) pi(-)h(c)中搜索Z(c) (3900)
DOI：
10.1103/physrevlett.111.242001
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发表时间：
2013-12-10
影响因子：
8.6
通讯作者：
Zou, J. H.
中科院分区：
文献类型：
--
作者：
Ablikim, M.;Achasov, M. N.;Zou, J. H.
利用北京正负电子对撞机BESIII探测器上的数据样本，研究了质心能量从3.90到4.42 GeV的e（+）e（-）-> pi（+）pi（-）h（c）.在13个能量下测量了玻恩截面，发现它们与e（+）e（-）-> pi（+）pi（-）J/Psi的玻恩截面具有相同的数量级，但具有不同的线形。在pi（+/-）h（c）质谱中，在4处观察到称为Z（c）（4020）的独特结构。02 GeV/c（2）. Z（c）（4020）携带电荷并与粲偶联。拟合pi（+/-）h（c）不变质谱，忽略可能的干扰，得到Z（c）（4020）的质量为（4022.9 +/- 0.8 +/- 2.7）MeV/c（2），宽度为（7.9 +/- 2.7 +/- 2.6）MeV，其中第一个误差是统计误差，第二个误差是系统误差。该结构的参数与在D*（D）over bar* 终态中观察到的Z（c）（4025）之间的差异在1.5 sigma之内，但它们是否是相同的状态需要进一步研究。没有观察到显著的Z（c）（3900）信号，并且设定了质心能量为4.23和4.26 GeV时以π +/- h（c）表示的Z（c）（3900）产生截面的上限。
We study e(+)e(-) -> pi(+) pi(-)h(c) at center-of-mass energies from 3.90 to 4.42 GeV by using data samples collected with the BESIII detector operating at the Beijing Electron Positron Collider. The Born cross sections are measured at 13 energies and are found to be of the same order of magnitude as those of e(+)e(-) -> pi(+) pi(-) J/Psi but with a different line shape. In the pi(+/-)h(c) mass spectrum, a distinct structure, referred to as Z(c)(4020) is observed at 4. 02 GeV/c(2). The Z(c)(4020) carries an electric charge and couples to charmonium. A fit to the pi(+/-)h(c) invariant mass spectrum, neglecting possible interferences, results in a mass of (4022.9 +/- 0.8 +/- 2.7) MeV/c(2) and a width of (7.9 +/- 2.7 +/- 2.6) MeV for the Z(c)(4020), where the first errors are statistical and the second systematic. The difference between the parameters of this structure and the Z(c) (4025) observed in the D*(D) over bar* final state is within 1.5 sigma, but whether they are the same state needs further investigation. No significant Z(c)(3900) signal is observed, and upper limits on the Z(c)(3900) production cross sections in pi +/- h(c) at center-of-mass energies of 4.23 and 4.26 GeVare set.