Investigation of 
Pcs(4459)0
 pentaquark via its strong decay to 
ΛJ/Ψ

K. Azizi,Y. Sarac,H. Sundu

doi:10.1103/physrevd.103.094033

Abstract

Recently the observation of a new pentaquark state, the hidden-charmed strange $P_{cs}(4459)^0$, was reported by the LHCb Collaboration. The spin-parity quantum numbers of this state were not determined as a result of insufficient statistics. To shed light on its quantum numbers, we investigate its decay, $P_{cs}(4459)^0 \rightarrow J/\psi \Lambda $, the mode that this state has been observed, within the QCD sum rule framework. We obtain the width of this decay assigning the spin-parity quantum numbers of $P_{cs}(4459)^0$ state as $J^P=\frac{1}{2}^-$ and its substructure as diquark-diquark-antiquark. To this end, we first calculate the strong coupling constants defining the considered decay and then use them in the width calculations. The obtained width is consistent with the experimental observation, confirming the quantum numbers $J^P=\frac{1}{2}^-$ and compact pentaquark nature for $P_{cs}(4459)^0$ state.

Highlights

In the past two decades, starting with the observation of the Xð3872Þ [1], we witnessed the observations of many exotic hadrons candidates for tetraquarks [2] and pentaquarks [3,4,5]
To shed light on its quantum numbers, we investigate its decay, Pcsð4459Þ0 → J=ψΛ, the mode that this state has been observed, within the quantum chromodynamics (QCD) sum rule framework
The first observation of pentaquark states was announced in 2015 by the LHCb Collaboration [3], and two pentaquark states in J=ψp invariant mass spectrum of the Λ0b → J=ψpK− decays were reported with the following resonance parameters [3]: mPcð4380Þþ 1⁄44380Æ8Æ29MeV, ΓPcð4380Þþ 1⁄4 205 Æ 18 Æ 86 MeV and mPcð4450Þþ 1⁄4 4449.8Æ 1.7 Æ 2.5 MeV, ΓPcð4450Þþ 1⁄4 39 Æ 5 Æ 19 MeV

Summary

INTRODUCTION

In the past two decades, starting with the observation of the Xð3872Þ [1], we witnessed the observations of many exotic hadrons candidates for tetraquarks [2] and pentaquarks [3,4,5]. The first observation of pentaquark states was announced in 2015 by the LHCb Collaboration [3], and two pentaquark states in J=ψp invariant mass spectrum of the Λ0b → J=ψpK− decays were reported with the following resonance parameters [3]: mPcð4380Þþ 1⁄44380Æ8Æ29MeV, ΓPcð4380Þþ 1⁄4 205 Æ 18 Æ 86 MeV and mPcð4450Þþ 1⁄4 4449.8Æ 1.7 Æ 2.5 MeV, ΓPcð4450Þþ 1⁄4 39 Æ 5 Æ 19 MeV. Together with the Pcð4312Þþ state, the LHCb announced the split of the peak corresponding to Pcð4450Þ− into two peaks, which have the following masses and widths: mPcð4440Þþ 1⁄4 4440.3 Æ 1.3þ−44..71. Understanding the inner structures and properties of these exotic states may support their future investigations. They may provide improvements in understanding the dynamics of the quantum chromodynamics (QCD) in its nonperturbative domain.

Published by the American Physical Society

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SUMMARY AND CONCLUSION

Another molecular interpretation was given in