Investigation of hidden-charm pentaquarks with strangeness $$S=-1$$

Abstract

Recently, a new hidden-charm pentaquark state $$P_{cs}(4459)$$ P cs ( 4459 ) was reported by the LHCb Collaboration. Stimulated by the fact that all hidden-charm pentaquark states in $$S=0$$ S = 0 systems were successfully studied by the chiral quark model, we extended this study to the $$S=-1$$ S = - 1 systems. All possible states with quantum numbers $$IJ^P=0(\frac{1}{2})^-$$ I J P = 0 ( 1 2 ) - , $$0(\frac{3}{2})^-$$ 0 ( 3 2 ) - , $$0(\frac{5}{2})^-$$ 0 ( 5 2 ) - , $$1(\frac{1}{2})^-$$ 1 ( 1 2 ) - , $$1(\frac{3}{2})^-$$ 1 ( 3 2 ) - and $$1(\frac{5}{2})^-$$ 1 ( 5 2 ) - have been investigated. The calculation results shows that the newly observed state $$P_{cs}(4459)$$ P cs ( 4459 ) can be explained as $$\Xi _c \bar{D}^*$$ Ξ c D ¯ ∗ molecular state and the quantum numbers are $$0(\frac{1}{2})^-$$ 0 ( 1 2 ) - . In addition, we also find other molecular states $$\Xi _c \bar{D}$$ Ξ c D ¯ , $$\Xi _c^* \bar{D}$$ Ξ c ∗ D ¯ and $$\Xi _c' \bar{D}^*$$ Ξ c ′ D ¯ ∗ . It is worth mentioning that $$\Xi _c \bar{D}^*$$ Ξ c D ¯ ∗ can form a two-peak structure from states in system $$0(\frac{1}{2})^-$$ 0 ( 1 2 ) - and $$0(\frac{3}{2})^-$$ 0 ( 3 2 ) - . The decay width of all molecular states is given with the help of real scaling method. These hidden-charm pentaquark states is expected to be further verified in future experiments.

An updated review of the new hadron states

“…The D * Ξ c molecular state of J P = 1/2 − was used in Ref. [682] to explain the P cs (4459), although the mass of the 3/2 − one was still calculated to be lighter, i.e., the masses of the J P = 1/2 − and 3/2 − states were calculated to be about 4461 MeV and 4443 MeV, respectively. However, the results of Ref.…”

The double thresholds distort the lineshapes of the $P_{ψs}^Λ(4338)^0$ resonance

“…[19][20][21][22][23][24]. The evidences of P Λ ψs (4459) 0 incited a new round of discussion [25][26][27][28][29][30][31].…”

Tetraquarks and Pentaquarks from Quark Model Perspective

“…The results of Ref. [319] are shown in Figures 9-11. In these figures, the thresholds of all physical channels appear as horizontal lines and are marked with lines (red lines), tagged with their contents.…”

“…The discovery of the first strange hidden-charm pentaquark immediately instigated active discussions on its structure and nature. Since the mass of P cs (4459) is only 19 MeV below the threshold of Ξ c D * , most works favored the P cs (4459) as the Ξ c D * molecular state [311][312][313][314][315][316][317][318][319]. Besides the molecular explanation, some works interpreted it as the compact pentaquark states [318,[320][321][322][323].…”

“…The real-scaling method was used to find the genuine resonance states in Ref. [319]. In this method, the scaling factor α is used to adjust the Gaussian size parameter r n of the basis functions between baryon and meson with r n → αr n .…”