论文标题
$ x（3872）$质量的精确度量及其计数率
On the precise measurement of the $X(3872)$ mass and its counting rate
论文作者
论文摘要
$ j^{pc} = 1^{++} $涉及三角形奇点的量子数，诸如$ x（3872）$之类的特定生产实验的线形，例如$ j^{pc} = 1^{++} $量子数，对弱约束状态的结合能量非常敏感，从而在基本上提供了基本标测定的机会。我们批判性地分析了最新的提案，以准确，准确地提取$ x（3872）$质量，这通过将其相应的生产线形视为急剧的质量分布，从而忽略了重要的物理效果，因此忽略了$ 1^{++} $通道中最初的附近连续态的影响。这些状态的包含意味着一种有效的取消机制，该机制在探测器的当前和有限的实验分辨率下运行，因此无法区分$ 1^{++} $绑定状态和附近的$ d \ bar d^*$ continuum continuum contenuum nate具有相同量子数。特别是，我们表明，除非考虑高统计数据，否则在1 MEV高于1 MEV的分辨率的线形对结合能的敏感。观察到的凸起的存在仅仅是短距离相关的$ \ bar d d d^*$对，绑定或未结合的结果。该取消还为最近的一项研究报告了$ x（3872）$的绝对分支比率分析的最新研究报告，该研究报告了丢失但未知的衰减渠道。
The lineshapes of specific production experiments of the exotic state such as $X(3872)$ with $J^{PC}=1^{++}$ quantum numbers involving triangle singularities have been found to become highly sensitive to the binding energy of weakly bound states, thus offering in principle the opportunity of benchmark determinations. We critically analyze recent proposals to extract accurately and precisely the $X(3872)$ mass, which overlook an important physical effect by regarding their corresponding production lineshapes as a sharp mass distribution and, thus, neglecting the influence of initial nearby continuum states in the $1^{++}$ channel. The inclusion of these states implies an effective cancellation mechanism which operates at the current and finite experimental resolution of the detectors so that one cannot distinguish between the $1^{++}$ bound-state and nearby $D \bar D^*$ continuum states with the same quantum numbers. In particular, we show that the lineshape for resolutions above 1 MeV becomes rather insensitive to the binding energy unless high statistics is considered. The very existence of the observed bumps is a mere consequence of short distance correlated $\bar D D^*$ pairs, bound or unbound. The cancellation also provides a natural explanation for a recent study reporting missing but unknown decay channels in an absolute branching ratio global analysis of the $X(3872)$.
