论文标题
探索$ξ^-_ {b} \ to K^ - j/ψλ$衰减中可能的三角奇异点
Exploring possible triangle singularities in the $Ξ^-_{b} \to K^- J/ψΛ$ decay
论文作者
论文摘要
我们分析了$ J/ψλ$中的可能的奇异性，该$ξ^-_ {b}〜\ to〜k^ - j/ψλ$通过三角环图表进行了。在18种不同的三角环图中发现了物理区域中的三角奇异性。在具有$ξ^*$ - charmonium- $λ$中间状态的人中，来自$χ_{c1}ξ（2120）λ$环（位于4628 MEV左右）的那些最有可能引起可观察到的效果。当这些系统的量子数为$ 1/2^+$或$ 3/2^+$时，一个人需要$ s $ - 和$ p $ -waves，分别为$χ_{C1}λ$和$ J/ψλ$系统。当$ξ（2120）$的量子号为$ j^p = 1/2^+$，$ 1/2^ - $或$ 3/2^+$时，峰结构应比其他$ j^p $选择更加明显。这表明，尽管整个强度尚不清楚，但我们应该注意$ξ^*$ - charmonium- $λ$三角形的贡献，如果在实验中观察到$ j/ψλ$不变质量谱中的结构。此外，一些带有$ d_ {s1}^*（2700）$的三角图作为中间粒子之一，也可以在$ j/ψλ$分布中产生奇异性，但在高于4.9 GEV的较高能量下。
We analyze possible singularities in the $J/ψΛ$ invariant mass distribution of the $Ξ^-_{b}~\to~K^- J/ψΛ$ process via triangle loop diagrams. Triangle singularities in the physical region are found in 18 different triangle loop diagrams. Among those with $Ξ^*$-charmonium-$Λ$ intermediate states, the one from the $χ_{c1} Ξ(2120) Λ$ loop, which is located around 4628 MeV, is found the most likely to cause observable effects. One needs $S$- and $P$-waves in $χ_{c1} Λ$ and $J/ψΛ$ systems, respectively, when the quantum numbers of these systems are $1/2^+$ or $3/2^+$. When the quantum numbers of the $Ξ(2120)$ are $J^P=1/2^+$, $1/2^-$ or $3/2^+$, the peak structure should be sharper than the other $J^P$ choices. This suggests that although the whole strength is unknown, we should pay attention to the contributions from the $Ξ^*$-charmonium-$Λ$ triangle diagram if structures are observed in the $J/ψΛ$ invariant mass spectrum experimentally. In addition, a few triangle diagrams with the $D_{s1}^*(2700)$ as one of the intermediate particles can also produce singularities in the $J/ψΛ$ distribution, but at higher energies above 4.9 GeV.
