P c s ( 4459 ) and other possible molecular states from Ξ c ( * ) D ¯ ( * ) and Ξ c ′ D ¯ ( * ) interactions
TL;DR: In this article, a coupled-channel study of the interactions in the quasipotential Bethe-Salpeter equation was performed, and the couplings of the molecular states to the considered channels were also discussed.
Abstract: Recently, the LHCb Collaboration reported a new structure ${P}_{cs}(4459)$ with a mass of 19 MeV below the ${\mathrm{\ensuremath{\Xi}}}_{c}{\overline{D}}^{*}$ threshold. It may be a candidate of molecular state from the ${\mathrm{\ensuremath{\Xi}}}_{c}{\overline{D}}^{*}$ interaction. In the current work, we perform a coupled-channel study of the ${\mathrm{\ensuremath{\Xi}}}_{c}^{*}{\overline{D}}^{*}$, ${\mathrm{\ensuremath{\Xi}}}_{c}^{\ensuremath{'}}{\overline{D}}^{*}$, ${\mathrm{\ensuremath{\Xi}}}_{c}^{*}\overline{D}$, ${\mathrm{\ensuremath{\Xi}}}_{c}{\overline{D}}^{*}$, ${\mathrm{\ensuremath{\Xi}}}_{c}^{\ensuremath{'}}\overline{D}$, and ${\mathrm{\ensuremath{\Xi}}}_{c}\overline{D}$ interactions in the quasipotential Bethe-Salpeter equation approach. With the help of the heavy quark chiral effective Lagrangian, the potential is constructed by light meson exchanges. Two ${\mathrm{\ensuremath{\Xi}}}_{c}{\overline{D}}^{*}$ molecular states are produced with spin parities ${J}^{P}=1/{2}^{\ensuremath{-}}$ and $3/{2}^{\ensuremath{-}}$. The lower state with $3/{2}^{\ensuremath{-}}$ can be related to the observed ${P}_{cs}(4450)$ while two-peak structure cannot be excluded. Within the same model, other strange hidden-charm pentaquarks are also predicted. Two states with spin parities $1/{2}^{\ensuremath{-}}$ and a state with $3/{2}^{\ensuremath{-}}$ are predicted near the ${\mathrm{\ensuremath{\Xi}}}_{c}^{\ensuremath{'}}\overline{D}$, ${\mathrm{\ensuremath{\Xi}}}_{c}\overline{D}$, and ${\mathrm{\ensuremath{\Xi}}}_{c}^{*}\overline{D}$ thresholds, respectively. As two states near ${\mathrm{\ensuremath{\Xi}}}_{c}{\overline{D}}^{*}$ threshold, two states are produced with $1/{2}^{\ensuremath{-}}$ and $3/{2}^{\ensuremath{-}}$ near the ${\mathrm{\ensuremath{\Xi}}}_{c}^{\ensuremath{'}}{\overline{D}}^{*}$ threshold. The couplings of the molecular states to the considered channels are also discussed. The experimental research of those states are helpful to understand the origin and internal structure of the ${P}_{cs}$ and ${P}_{c}$ states.
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TL;DR: In this article, a new member of the known hidden-charm pentaquarks, called the $P_{cs}(4459)$ by the LHCb collaboration, was observed.
Abstract: The observation of the $P_{cs}(4459)$ by the LHCb collaboration adds a new member to the set of known hidden-charm pentaquarks, which includes the $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$. The $P_{cs}(4459)$ is expected to have the light-quark content of a $\Lambda$ baryon ($I=0$, $S=-1$), but its spin is unknown. Its closeness to the $\bar{D}^* \Xi_c$ threshold -- $4478\,{\rm MeV}$ in the isospin-symmetric limit -- suggests the molecular hypothesis as a plausible explanation for the $P_{cs}(4459)$. While in the absence of coupled-channel dynamics heavy-quark spin symmetry predicts the two spin-states of the $\bar{D}^* \Xi_c$ to be degenerate, power counting arguments indicate that the coupling with the nearby $\bar{D} \Xi_c'$ and $\bar{D} \Xi_c^*$ channels might be a leading order effect. This generates a hyperfine splitting in which the $J=\tfrac{3}{2}$ $\bar{D}^* \Xi_c$ pentaquark will be lighter than the $J=\tfrac{1}{2}$ configuration, which we estimate to be of the order of $5-15\,{\rm MeV}$. We also point out an accidental symmetry between the $P_{cs}(4459)$ and $P_c(4440/4457)$ potentials. Finally, we argue that the spectroscopy and the $J/\psi \Lambda$ decays of the $P_{cs}(4459)$ might suggest a marginal preference for $J = \tfrac{3}{2}$ over $J = \tfrac{1}{2}$.
40 citations
TL;DR: In this paper, the LHCb observation of the hidden-charm pentaquarks was used to add a new member to the set of known hidden-chant pentaquark, which includes the $$P_c(4312)$$�, $$P-c(4440/4457)$$Buyable potentials.
Abstract: The observation of the $$P_{cs}(4459)$$
by the LHCb collaboration adds a new member to the set of known hidden-charm pentaquarks, which includes the $$P_c(4312)$$
, $$P_c(4440)$$
and $$P_c(4457)$$
. The $$P_{cs}(4459)$$
is expected to have the light-quark content of a $$\Lambda $$
baryon (
$$I=0$$
, $$S=-1$$
), but its spin is unknown. Its closeness to the $${\bar{D}}^* \Xi _c$$
threshold – $$4478\,{\mathrm{MeV}}$$
in the isospin-symmetric limit – suggests the molecular hypothesis as a plausible explanation for the $$P_{cs}(4459)$$
. While in the absence of coupled-channel dynamics heavy-quark spin symmetry predicts the two spin-states of the $${\bar{D}}^* \Xi _c$$
to be degenerate, power counting arguments indicate that the coupling with the nearby $${\bar{D}} \Xi _c'$$
and $${\bar{D}} \Xi _c^*$$
channels might be a leading order effect. This generates a hyperfine splitting in which the $$J=\tfrac{3}{2}$$
$${\bar{D}}^* \Xi _c$$
pentaquark will be lighter than the $$J=\tfrac{1}{2}$$
configuration, which we estimate to be of the order of $$5-15\,{\mathrm{MeV}}$$
. We also point out an accidental symmetry between the $$P_{cs}(4459)$$
and $$P_c(4440/4457)$$
potentials. Finally, we argue that the spectroscopy and the $$J/\psi \Lambda $$
decays of the $$P_{cs}(4459)$$
might suggest a marginal preference for $$J = \tfrac{3}{2}$$
over $$J = \tfrac{1}{2}$$
.
37 citations
TL;DR: In this paper, the authors obtained the width of the hidden-charmed-strange (HCS) state with respect to the spin-parity quantum number of the HCS state.
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, ${P}_{cs}(4459{)}^{0}\ensuremath{\rightarrow}J/\ensuremath{\psi}\mathrm{\ensuremath{\Lambda}}$, 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 the ${P}_{cs}(4459{)}^{0}$ state as ${J}^{P}={\frac{1}{2}}^{\ensuremath{-}}$ 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 ${J}^{P}={\frac{1}{2}}^{\ensuremath{-}}$ and compact pentaquark nature for the ${P}_{cs}(4459{)}^{0}$ state.
23 citations
20 citations
TL;DR: In this paper, the authors studied the line shape of a hidden charm pentaquark state with strangeness and showed that the production yield of a spin $3/2$ state is approximately one order of magnitude larger than that of spin $1/ 2$ state due to the interference of the interference.
Abstract: Recently, the LHCb Collaboration reported on the evidence for a hidden charm pentaquark state with strangeness, i.e., ${P}_{cs}(4459)$, in the $J/\ensuremath{\psi}\mathrm{\ensuremath{\Lambda}}$ invariant mass distribution of the ${\mathrm{\ensuremath{\Xi}}}_{b}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}\mathrm{\ensuremath{\Lambda}}{K}^{\ensuremath{-}}$ decay. In this work, assuming that ${P}_{cs}(4459)$ is a ${\overline{D}}^{*}{\mathrm{\ensuremath{\Xi}}}_{c}$ molecular state, we study this decay via triangle diagrams ${\mathrm{\ensuremath{\Xi}}}_{b}\ensuremath{\rightarrow}{\overline{D}}_{s}^{(*)}{\mathrm{\ensuremath{\Xi}}}_{c}\ensuremath{\rightarrow}({\overline{D}}^{(*)}\overline{K}){\mathrm{\ensuremath{\Xi}}}_{c}\ensuremath{\rightarrow}{P}_{cs}\overline{K}\ensuremath{\rightarrow}(J/\ensuremath{\psi}\mathrm{\ensuremath{\Lambda}})\overline{K}$. Our study shows that the production yield of a spin $3/2$ ${\overline{D}}^{*}{\mathrm{\ensuremath{\Xi}}}_{c}$ state is approximately one order of magnitude larger than that of a spin $1/2$ state due to the interference of ${\overline{D}}_{s}{\mathrm{\ensuremath{\Xi}}}_{c}$ and ${\overline{D}}_{s}^{*}{\mathrm{\ensuremath{\Xi}}}_{c}$ intermediate states. We obtain a model independent constraint on the product of couplings ${g}_{{P}_{cs}{\overline{D}}^{*}{\mathrm{\ensuremath{\Xi}}}_{c}}$ and ${g}_{{P}_{cs}J/\ensuremath{\psi}\mathrm{\ensuremath{\Lambda}}}$. With the predictions of two particular molecular models as inputs, we calculate the branching ratio of ${\mathrm{\ensuremath{\Xi}}}_{b}^{\ensuremath{-}}\ensuremath{\rightarrow}({P}_{cs}\ensuremath{\rightarrow})J/\ensuremath{\psi}\mathrm{\ensuremath{\Lambda}}{K}^{\ensuremath{-}}$ and compare it with the experimental measurement. We further predict the line shape of this decay that could be useful to future experimental studies.
16 citations
References
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TL;DR: In this article, the pentaquark-charmonium states were observed in the J/ψp channel in Λ0b→J/K−p decays and the significance of these resonances is more than 9 standard deviations.
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847 citations
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693 citations
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517 citations
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511 citations