论文标题
$ p_ {ψs}^λ（4338）$和可能的$ p_ {ψs}}^λ（4255）$ in $ b^ - \ to j/ψλ\ bar {p} $的极点确定
Pole determination of $P_{ψs}^Λ(4338)$ and possible $P_{ψs}^Λ(4255)$ in $B^-\to J/ψΛ\bar{p}$
论文作者
论文摘要
最近在$ b^ - \至j/ψλ\ bar {p} $中发现了第一个具有陌生性的隐藏式冠军pentaquark候选者，$ p_ {ψs}^λ（4338）$。 $ p_ {ψs}^λ（4338）$在$ J/ψλ$不变质量（$ m_ {j/ψλ} $）中以$ξ_c\ bar {d} $ threshold表示为颠簸。 $ m_ {j/ψλ} $分布还显示了$λ_c\ bar {d} _s $ threshold的大波动，暗示可能存在可能的$ p_ {ψs}^λ（4255）$。在这项工作中，我们首次确定$ p_ {ψs}^λ（4338）$和$ p_ {ψs}^λ（4255）$ pole pole tirce是第一次。为此，我们适合a $ b^ - \与j/ψλ\ bar {p} $模型适用于$ m_ {j/ψλ} $，$ m_ {j/ψ\ bar {p}} $，$ m_ {λ\ bar bar {p} $χ^2/{\ rm ndf} \ sim 1.21 $。然后，我们从单位$ξ_c\ bar {d} $ - $λ_c\ bar {d} _s $ coupled-nanger-ncled-nanger散射幅度中提取$ p_ {ψs}^λ$ pol。在我们的默认合适中，$ p_ {ψs}^λ（4338）$ pole的$（4338.2 \ pm 1.4） - （1.9 \ pm 0.5）\，i $ mev，而$ p_ {ψs}^λ（4255）$ 4254.7 \ pm 0.4 \ pm 0.4 \ mev $ pole。 $ p_ {ψs}^λ（4338）$和$ p_ {ψs}^λ（4255）$分别是$ $ξ_c\ bar {d} $ bond和$λ_c\ bar {d} d}通过我们的分析，数据将$ p_ {ψs}^λ（4338）$的假设视为运动效应。该极点确定本身很重要，它设定了研究$ p_ {ψs}^λ$状态的主要基础。
First hidden-charm pentaquark candidate with strangeness, $P_{ψs}^Λ(4338)$, was recently discovered in $B^-\to J/ψΛ\bar{p}$ by the LHCb Collaboration. $P_{ψs}^Λ(4338)$ shows up as a bump at the $Ξ_c\bar{D}$ threshold in the $J/ψΛ$ invariant mass ($M_{J/ψΛ}$) distribution. The $M_{J/ψΛ}$ distribution also shows a large fluctuation at the $Λ_c\bar{D}_s$ threshold, hinting the existence of a possible $P_{ψs}^Λ(4255)$. In this work, we determine the $P_{ψs}^Λ(4338)$ and $P_{ψs}^Λ(4255)$ pole positions for the first time. For this purpose, we fit a $B^-\to J/ψΛ\bar{p}$ model to the $M_{J/ψΛ}$, $M_{J/ψ\bar{p}}$, $M_{Λ\bar{p}}$, and $\cosθ_{K^*}$ distributions from the LHCb simultaneously; $χ^2/{\rm ndf}\sim 1.21$. Then we extract $P_{ψs}^Λ$ poles from a unitary $Ξ_c\bar{D}$-$Λ_c\bar{D}_s$ coupled-channel scattering amplitude built in the model. In our default fit, the $P_{ψs}^Λ(4338)$ pole is found at $( 4338.2\pm 1.4)-( 1.9\pm 0.5 )\,i$ MeV while the $P_{ψs}^Λ(4255)$ pole at $4254.7\pm 0.4$ MeV. The $P_{ψs}^Λ(4338)$ and $P_{ψs}^Λ(4255)$ are mostly $Ξ_c \bar{D}$ bound and $Λ_c\bar{D}_s$ virtual states, respectively. Through our analysis, the data disfavors a hypothesis of $P_{ψs}^Λ(4338)$ as merely a kinematical effect. This pole determination, which is important in its own right, sets a primary basis to study the nature of the $P_{ψs}^Λ$ states.
