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arXiv · 2109.03456

Novel description of $P_c(4312)^+$, $P_c(4380)^+$, and $P_c(4457)^+$ with double triangle cusps

Satoshi X. Nakamura
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Abstract

We propose a novel scenario for the peak structures, usually interpreted as hidden charm pentaquark ($P_c$) contributions, in the LHCb's $Λ_b^0\to J/ψp K^-$ data. The key idea is to utilize leading or lower-order singularities from double triangle mechanisms. The singularities cause anomalous threshold cusps, which are significantly more singular than the ordinary ones, at the $Σ_c^{(*)}\bar{D}^{(*)}$ threshold. We demonstrate that the double triangle amplitudes interfere with other common mechanisms to create peak structure that fit well the $P_c(4312)^+$, $P_c(4380)^+$, and $P_c(4457)^+$ peaks in the data. This picture is completely different from commonly used ones such as hadron molecules and compact pentaquarks. Meanwhile, $P_c(4440)^+$ is included in the proposed model as a resonance with width and strength significantly smaller than previously estimated. The proposed model can (partly) explain the current data for other processes where $P_c^+$ signals are expected such as: no $P_c^+$ signals in the GlueX $J/ψ$ photoproduction data; a possible signal only from $P_c(4440)^+$ in the LHCb's $Λ_b^0\to J/ψp π^-$ data.

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Satoshi X. Nakamura. 2021-09-08. Novel description of $P_c(4312)^+$, $P_c(4380)^+$, and $P_c(4457)^+$ with double triangle cusps. https://doi.org/10.22323/1.385.0029

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