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在B^{0}→J/ψφK_{S}^{0}衰变中的J/ψK_{S}^{0}结构的证据

R Aaij¹, A S W Abdelmotteleb², C Abellan Beteta³

¹Nikhef National Institute for Subatomic Physics, Amsterdam, Netherlands.

Physical review letters

|October 13, 2023

概括

研究人员观察到一个新的粒子,T_{ψs1}^{θ}(4000) ^{0},在B^{0}→J/ψφK_{S}^{0}衰变中. 这一发现为粒子物理学中的一个新结构提供了证据,并且可能是以前见过的状态的同回旋伙伴.

科学领域:

高能物理高能物理
粒子物理学粒子物理学
量子色态动力学量子色态动力学

背景情况:

B^{0}→J/ψφK_{S}^{0}衰变是一个复杂的过程,涉及多个共振.
之前在相关的B质子衰变中对异国情态的观察表明,存在新的子结构.

研究的目的:

进行B^{0}→J/ψφK_{S}^{0}衰变的振幅分析,以寻找新的共振结构.
描述任何观察到的结构的属性 (质量和宽度).
为了研究中性和带电异常状态在B-meson系统之间的关系.

主要方法:

分析了由LHCb探测器在7,8和13 TeV收集的大量质子-质子碰撞数据集 (9 fb^{-1}).
对B^{0}→J/ψφK_{S}^{0}衰变的幅度分析以确定共振贡献.
统计学意义计算以确认新结构的存在.

主要成果:

在J/ψK_{S}^{0}系统中,证据表明一个新的结构,名为T_{ψs1}^{θ}(4000) ^{0},具有4.0标准偏差的意义.
测量T_{ψs1}^{θ}(4000) ^{0}的质量和宽度分别为3991_{-10}^{+12} MeV/c^{2}和105_{-25}^{+29} MeV.
假设同回旋对称,中性和充电T_{ψs1}^{θ}(4000) 状态的综合显著性增加到5.4个标准偏差.

结论:

对T_{ψs1}^{θ}(4000) ^{0}的观测提供了新的异常子状态的有力证据.
这个T_{ψs1}^{θ}(4000) ^{0}可能是之前观察到的T_{ψs1}^{θ}(4000) ^{+}状态的同回旋伙伴.
这一发现有助于理解标准模型中异国子的复杂光谱.

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