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arXiv 2402.03057hep-phhep-ex
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4.2至4.35 GeV能区存在多少个矢量粲偶素(类粲偶素)态?

How many vector charmonium(-like) states sit in the energy range from $4.2$ to $4.35$ GeV?

Leon von Detten, Vadim Baru, Christoph Hanhart, Qian Wang, Daniel Winney, Qiang Zhao

AI总结:

本研究针对4.2-4.35 GeV能区矢量粲偶素态数量争议,通过多末态综合分析结合阈效应与干涉机制,证实该能区仅存在一个类$D_1\bar D$分子结构的Y(4230)态,并解释了相关截面不对称性的SU(3)味对称起源。

摘要:

近年来,多个正负电子对撞机实验在4.2 GeV以上能区报道了众多矢量粲偶素(类粲偶素)态。但截至目前,这些态的参数不仅存在较大分歧,该能区矢量态的数量也未达成共识。在一定程度上,这可能是因为实验数据通常采用叠加Breit-Wigner(布雷特-维格纳)函数的单道分析方法,尤其忽略了开阈效应的影响。本研究聚焦4.2至4.35 GeV的质量区间,对正负电子湮灭的8种不同末态开展综合分析。研究结果表明,该质量区间内仅需一个矢量类粲偶素态即可有效描述所有收集到的数据,该态的性质与$D_1\bar D$分子结构相符,极点位置为$\sqrt{s_\text{pole}^{Y(4230)}}=\left( 4227{\pm}3 {-} \frac{i}{2}(50^{+10}_{-5}) \right) \text{MeV}$。这一结论是通过纳入与已确立的矢量粲偶素$ψ(4160)$的干涉效应,以及考虑$D_1\bar D$阈效应实现的。此外,与实验分析不同,本研究发现4230 MeV附近$e^+e^-\to J/ψππ$和$e^+e^-\to J/ψK\bar K$过程的高度不对称总截面源于相同的物理机制,其根源是QCD(量子色动力学)的近似SU(3)味对称性。

英文摘要:

In recent years many vector charmonium(-like) states were reported by different electron-positron collider experiments above $4.2$ GeV. However, so far, there not only exists sizable tension in the parameters of those states, but there is also no consensus on the number of the vector states in this energy range. To some extend, this might be caused by the fact that the experimental data were typically analyzed in single channel analyses employing overlapping Breit-Wigner functions, in particular ignoring the effect of opening thresholds. In this study, we focus on the mass range between $4.2$ and $4.35$ GeV, conducting a comprehensive analysis of eight different final states in $e^+ e^-$ annihilation. Our findings demonstrate that, within this mass range, a single vector charmonium-like state, exhibiting properties consistent with a $D_1\bar D$ molecular structure and characterized by a pole location $\sqrt{s_\text{pole}^{Y(4230)}}=\left( 4227{\pm} 3 {-} \frac{i}{2}(50^{+10}_{-5}) \right) \text{MeV}$, can effectively describe all the collected data. This is made possible by allowing for an interference with the well-established vector chamonium $ψ(4160)$ along with the inclusion of the $D_1\bar D$ threshold effect. Moreover, in contrast to experimental analyses, our study reveals that the highly asymmetric total cross sections for $e^+e^-\to J/ψππ$ and $e^+e^-\to J/ψK\bar K$ around 4230 MeV stem from the same physics, rooted in the approximate SU(3) flavor symmetry of QCD.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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