论文标题
双阈值扭曲了$ p_ {ψs}^λ（4338）^0 $共振的线形
The double thresholds distort the lineshapes of the $P_{ψs}^Λ(4338)^0$ resonance
论文作者
论文摘要
最近，LHCB合作报告了对隐藏的魅力pentaquark的首次观察，$ p_ {ψs}^λ（4338）^0 $。考虑到这种状态非常接近$ξ_c^0 \ bar {d}^0 $和$ξ_c^+d^ - $ thresholds，我们探索了Breit-wigner参数化的可能偏差，重点是其耦合到双thresholds $ thresholds $ thresholds $ξ_c^0 \ bar^0 \ $^0 $^0 $^0.我们首先根据两道通道系统的riemann表面的``统一化''首先使用定性图片来了解增强的位置。然后，我们使用lippmann-schwinger方程（LSE）形式主义（等效于$ k $ -mtrix参数）与两个模型，$ j级别的模型和flatte the unge conters comport $ j-matrix commination comport us $ j/jecome use unde unge comport usecte us $ j/y llateψ $ p_ {ψs}^λ（4338）^0 $的名义峰可能是从$（ - ，+）$表上的$（ - +）$ the of $（ - +）$ the $（$ξ_c^0 \ bar bar {d}^0 $ threshold上的$（ - ）$（ - ）$（ - - ）$（ - - - ）$的the Polet的$（ - ，+）$上的阈值。描绘上述两条线条可能是误导的。 $ {γ_{p_ {ψs}^λ\ to j/ψς}}}/{γ_{p_ {ψs}^λ\ to j/ψλ}}} $最多可高达$ 10 \％$。
Very recently, the LHCb Collaboration reported the first observation of the hidden charm pentaquark with strangeness, $P_{ψs}^Λ(4338)^0$. Considering this state is very close to the $Ξ_c^0\bar{D}^0$ and $Ξ_c^+D^-$ thresholds, we explore the possible bias of the Breit-Wigner parameterization, with emphasis on the effect of its coupling to the double thresholds $Ξ_c^0\bar{D}^0$ and $Ξ_c^+D^-$. We first use a qualitative picture based on the ``uniformization" of the Riemann surface of the two-channel system to understand the positions of the enhancement. Then we use the Lippmann-Schwinger equation (LSE) formalism (equivalent to the $K$-matrix parameterization) with two models, the zero-range model and Flatté model to investigate the $J/ψΛ$ lineshapes. Our results show that the nominal peak of the $P_{ψs}^Λ(4338)^0$ could arise either from the pole well above the $Ξ_c^+ D^-$ threshold on the $(-,+)$ sheet or from the pole well below the $Ξ_c^0 \bar{D}^0$ threshold on the $(-,-)$ sheet in the two-channel system. Using the Breit-Wigner distribution to depict the above two lineshapes could be misleading. We also find a novel type of lineshapes with the enhancement constrained by the threshold difference. We urge the LHCb collaboration to perform the refined experimental analysis considering the unitarity and analyticity, e.g. using the K-matrix parameterization. As a by-product, we obtain that the ratio of the isospin violating decay ${Γ_{P_{ψs}^Λ\to J/ψΣ}}/{Γ_{P_{ψs}^Λ\to J/ψΛ}}$ could be up to $10\%$.
