We study the $P_{cs}(4459)^0$ recently observed by LHCb using the method of QCD sum rules. Our results support its interpretation as the $\bar D^* Ξ_c$ hadronic molecular state of either $J^P=1/2^-$ or $3/2^-$. Within the hadronic molecular picture, the three LHCb experiments observing $P_c$ and $P_{cs}$ states \cite{lhcb,Aaij:2015tga,Aaij:2019vzc} can be well understood as a whole. This strongly supports the existence of hadronic molecules, whose studies can significantly improve our understanding on the construction of the subatomic world. To verify this picture, we propose to further investigate the $P_{cs}(4459)^0$ to examine whether it can be separated into two states, and to search for the $\bar D Ξ_c$ molecular state of $J^P=1/2^-$.
Inspired by the observation of the $P_{cs}(4459)$ and $P_{ψs}^Λ(4338)$, we systematically investigate the magnetic moments, the transition magnetic moments, and the radiative decay behaviors of the $S$-wave isoscalar $Ξ_c^{(\prime)}\bar D^{(*)}$ molecular pentaquark states in this work. Our quantitative investigation shows that their electromagnetic properties can provide important hint to decode the inner structure of these discussed isoscalar $Ξ_c^{(\prime)}\bar D^{*}$ molecular pentaquarks. As the potential research issue, we suggest future experiment to focus on the electromagnetic propert…
Motivated by the successful interpretation of these observed $P_c$ and $P_{cs}$ states under the meson-baryon molecular picture, we systematically investigate the possible hidden-charm molecular pentaquark states with triple strangeness which is due to the $Ω_{c}^{(*)}\bar{D}_s^{(*)}$ interactions. We perform a dynamical calculation of the possible hidden-charm molecular pentaquarks with triple strangeness by the one-boson-exchange model, where the $S$-$D$ wave mixing effect and the coupled channel effect are taken into account in our calculation. Our results suggest that the $Ω_{c}\bar D_s^*$…
Inspired by the recent evidence of $P_{cs}(4459)$ reported by LHCb, we continue to perform the investigation of hidden-charm molecular pentaquarks with double strangeness, which are composed of an $S$-wave charmed baryon $Ξ_c^{(\prime,*)}$ and an $S$-wave anti-charmed-strange meson $\bar{D}_s^{(*)}$. Both the $S$-$D$ wave mixing effect and the coupled channel effect are taken into account in realistic calculation. A dynamics calculation shows that there may exist two types of hidden-charm molecular pentaquark with double strangeness, i.e., the $Ξ_{c}^{*}\bar D_s^*$ molecular state with $J^P={5…
Inspired by the newly observed $P_{ψs}^Λ(4338)$ and the reported $P_{cs}(4459)$, we indicate the existence of the molecular-type characteristic mass spectrum for hidden-charm pentaquark with strangeness. It shows that the $P_{cs}(4459)$ may contain two substructures corresponding to the $Ξ_c\bar{D}^*$ molecular states with $J^P=1/2^-$ and $3/2^-$, while there exists the corresponding $Ξ_c \bar{D}$ molecular state with $J^P=1/2^-$. As the prediction, we present another characteristic mass spectrum of the $Ξ_c^\prime\bar{D}^{(*)}$ molecular states. Experimental confirmation of these characterist…
We review the experimental evidence on firstly, strangeness production as a signature for the QCD phase transition and secondly, pentaquarks, the latest and most exotic manifestations of strangeness in hadrons.
In this article, we investigate the $\bar{D}Σ_c$, $\bar{D}Ξ^\prime_c$, $\bar{D}Σ_c^*$, $\bar{D}Ξ_c^*$, $\bar{D}^{*}Σ_c$, $\bar{D}^{*}Ξ^\prime_c$, $\bar{D}^{*}Σ_c^*$ and $\bar{D}^{*}Ξ_c^*$ pentaquark molecular states with strangeness and without strangeness via the QCD sum rules at length, pay much attention to the light flavor $SU(3)$ breaking effects, and make predictions for new pentaquark molecular states besides assigning the $P_c(4312)$, $P_c(4380)$, $P_c(4440)$, $P_c(4457)$ and $P_{cs}(4459)$ self-consistently. We can search for those pentaquark molecular states in the decays of the $Λ_b…
We study the $Λ_{b}\rightarrow J/ψK^{0}Λ$ reaction considering both the $K^{0}Λ$ interaction with its coupled channels and the $J/ψΛ$ interaction. The latter is described by taking into account the fact that there are predictions for a hidden-charm state with strangeness that couples to $J/ψΛ$. By using the coupling of the resonance to $J/ψΛ$ from these predictions we show that a neat peak can be observed in the $J/ψΛ$ invariant mass distribution, rather stable under changes of unknown magnitudes. In some cases, one finds a dip structure associated to that state, but a signal of the state show…
In two recent papers, we used the hadro-quarkonium model to study the properties of hidden-charm and bottom tetraquarks and pentaquarks. Here, we extend the previous results and calculate the masses of heavy-quarkonium-kaon/hyperon systems. We also compute the spectrum of hidden-charm and bottom tetraquarks with strangeness in the compact tetraquark (diquark-antidiquark) model. If heavy-light exotic systems with non-null strangeness content were to be observed experimentally, it might be possible to distinguish among the large variety of available theoretical pictures for tetra- and pentaquark…
The existence of pentaquarks with strangeness content zero and one are major discoveries of the latest years in hadron physics. Most of these states can be understood as hadronic molecules and were predicted prior to their discovery within a model based on unitarized meson-baryon amplitudes obtained from vector meson exchange interactions. Contrary to earlier statements, we show this model to also predict the existence of pentaquarks with double strangeness, at about 4500 MeV and 4600 MeV, which are generated in a very specific and unique mechanism, via an attraction induced by a strong coupli…
The masses of cryptoexotic pentaquarks with hidden beauty are estimated phenomenologically using the results by the LHCb collaboration which discovered recently the cryptoexotic pentaquarks with hidden charm. The expected masses of the hidden beauty pentaquarks are about $10.8$ GeV and $10.7$ GeV in the limit of some kind of heavy quark symmetry. The states with hidden strangeness considered in similar way have masses about $2.37$ Gev and $2.30$ GeV, by several hundreds of MeV higher than states discussed previously in connection with the relatively light positive strangeness pentaquark $θ^+$.…
We study the mass spectra of hidden-charm pentaquarks having spin $J = {1\over2}/{3\over2}/{5\over2}$ and quark contents $uud c \bar c$. We systematically construct all the relevant local hidden-charm pentaquark currents, and select some of them to perform QCD sum rule analyses. We find that the $P_c(4380)$ and $P_c(4450)$ can be identified as hidden-charm pentaquark states composed of an anti-charmed meson and a charmed baryon. Besides them, we also find a) the lowest-lying hidden-charm pentaquark state of $J^P = 1/2^-$ has the mass $4.33^{+0.17}_{-0.13}$ GeV, while the one of $J^P = 1/2^+$ i…
Motivated by the observation of the first hidden charm pentaquarks by the LHCb collaboration in 2015 and the updated analysis with an order-of-magnitude larger data set in 2019, we estimate their cross sections for the prompt production as well as their heavy quark spin partners, in the $Σ_c^{(*)}\bar{D}^{(*)}$ hadronic molecular picture, at the center-of-mass energy $7~\mathrm{TeV}$ in the $pp$ collision. Their cross sections are several $\mathrm{nb}$ and we would expect several tens hidden charm pentaquark events in the LHC based on its current integrated luminosity. The cross sections show …
Assuming that the recently observed hidden-charm pentaquark state, $P_c(4450)$, is of molecular nature as predicted in the unitary approach, we propose to study the decay of $Ξ^-_b\rightarrow J/ψK^- Λ$ to search for the strangeness counterpart of the $P_c(4450)$. There are three ingredients in the decay mechanism: the weak decay mechanism, the hadronization mechanism, and the finite state interactions in the meson-baryon system of strangeness $S=-2$ and isospin $I=1/2$ and of the $J/ψΛ$. All these have been tested extensively. As a result, we provide a genuine prediction of the differential cr…
In the paper, we construct eight color singlet-singlet type five-quark currents with distinguished isospins to study the $\bar{D}Ξ^{\prime}$, $\bar{D}Ξ_c^{*}$, $\bar{D}^{*}Ξ_c^{\prime}$ and $\bar{D}^{*}Ξ_c^{*}$ molecular states with strangeness via the QCD sum rules. Numerical results show that the central values of the pentaquark masses with higher (lower) isospin are slightly above (below) the thresholds of the corresponding meson-baryon pairs, and support assigning the $P_{cs}(4459)$ as the $\bar{D}Ξ_c^{*}$ molecular state with the quantum numbers $IJ^P=0{\frac{3}{2}}^-$. The other predicti…
Motivated by the recent discovery of the first hidden charm pentaquark state with strangeness $P_{cs}(4459)$ by the LHCb Collaboration, we study the likely existence of a three-body $Σ_{c}\bar{D}\bar{K}$ bound state, which shares the same minimal quark content as $P_{cs}(4459)$. The $Σ_{c}\bar{D}$ and $DK$ interactions are determined by reproducing $P_c(4312)$ and $D_{s0}^*(2317)$ as $Σ_c\bar{D}$ and $\bar{D}\bar{K}$ molecules, respectively, while the $Σ_c\bar{K}$ interaction is constrained by chiral effective theory. We indeed find a three-body bound state by solving the Schrödinger equation …
In the framework of the color-magnetic interaction, we have systematically studied the mass splittings of the possible hidden-charm pentaquarks $qqqc\bar{c}$ ($q=u,d,s$) where the three light quarks are in a color-octet state. We find that i) the LHCb $P_c$ states fall in the mass region of the studied system; ii) most pentaquarks should be broad states since their $S$-wave open-charm decays are allowed while the lowest state is the $J^P=\frac12^-$ $Λ$-like pentaquark with probably the suppressed $η_cΛ$ decay mode only; and iii) the $J^P=\frac52^-$ states do not decay through $S$-wave and thei…
In the framework of one-pion-exchange (OPE) model, we study the hidden-charm and charm-strange molecular pentaquark systems composed of a heavy baryon $(Σ_c, Σ_c^*)$ and a vector meson $(\bar{K}^*, \bar{D}^*)$, where the S-D mixing effect is considered in our calculation. Our result shows that the $Σ_c\bar{D}^*$ molecular state with $(I=1/2,J^P=3/2^-)$ and the $Σ_c^*\bar{D}^*$ molecular state with $(I=1/2,J^P=5/2^-)$ exist in the mass range of the observed $P_c(4380)$ and $P_c(4450)$, respectively. Moreover, we predict two other hidden-charm molecular pentaquarks with configurations $Σ_c\bar{D…
We revisit the hidden-charm pentaquark states $P_c(4380)$ and $P_c(4450)$ using the method of QCD sum rules by requiring the pole contribution to be larger than or around 30\% to better insure the one-pole parametrization to be valid. We find two mixing currents and our results suggest that the $P_c(4380)$ and $P_c(4450)$ can be identified as hidden-charm pentaquark states having $J^P=3/2^-$ and $5/2^+$, respectively, while there still exist other possible spin-parity assignments, such as $J^P=3/2^+$ and $J^P=5/2^-$, which needs to be clarified in further theoretical and experimental studies.
The possibility of observing formation of hidden-charm pentaquarks as $s$-channel resonances in antiproton - deuteron collisions is discussed. It is pointed out that the masses of the reported by LHCb pentaquark resonances in the $J/ψ\, p$ channel are very close to a special value of the mass at which formation of a pentaquark by antiproton incident on a deuteron at rest requires exactly the same momentum of the $\bar p$ as needed for the formation in the $s$ channel of the charmonium resonance in $\bar p p$ collisions with the proton being at rest. For this reason the former process can be ra…
It is pointed out that the previously suggested interpretation of the hidden-charm pentaquarks $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$ as molecular bound states of $Σ_c \bar D$ and $Σ_c \bar D^*$ baryon-meson pairs gives rise to specific relations for their decays. In particular, the heavy quark spin symmetry predicts ratios of rates of decays of each of the molecules to $J/ψp$ and to $η_c p$ as well as of the decays to $Λ_c \bar D$ and to $Λ_c \bar D^*$. Experimental studies of these relations would thus provide an indicative probe of the molecular structure.
We investigate the production of the hidden-charm pentaquark $P_{cs}^0(4459)$ with strangeness in the $K^- p \to J/ψΛ$ reaction, employing two different theoretical frameworks, i.e., the effective Lagrangian method and the Regge approach. Having determined all relevant coupling constants, we are able to compute the total and differential cross sections for the $K^- p \to J/ψΛ$ reaction. We examine the contributions of $P_{cs}$ with different sets of spin-parity quantum number assigned. The present results may give a guide for possible future experiments.
The cross section for formation in $γ+ p$ collisions of the recently found hidden-charm pentaquark states $P_c(4380)$ and $P_c(4450)$ is discussed and estimated. The studies of these resonances in photon beam experiments can be complementary to those in the LHCb experiment setting, and may be more advantageous for measurement of their additional decay channels. It is pointed out that both the relative importance of such decays and the yield of the resonances in the $γ+ p$ collisions are sensitive to the internal dynamics of the pentaquarks and can resolve between theoretical models. Specific n…
We perform a systematic exploration of the possible doubly charmed molecular pentaquarks composed of $Σ_c^{(*)}D^{(*)}$ with the one-boson-exchange potential model. After taking into account the $S-D$ wave mixing and the coupled channel effects, we predict several possible doubly charmed molecular pentaquarks, which include the $Σ_cD$ with $I(J^P) = 1/2(1/2^-)$, $Σ_c^*D$ with $1/2(3/2^-)$, and $Σ_cD^*$ with $1/2(1/2^-)$, $1/2(3/2^-)$. The $Σ_cD$ state with $3/2(1/2^-)$ and $Σ_cD^*$ state with $3/2(1/2^-)$ may also be suggested as candidates of doubly charmed molecular pentaquarks. The $Σ_cD$ a…
In this work, we discuss the electromagnetic properties of the $S$-wave $Σ_c^{(*)}D^{(*)}$-type doubly charmed molecular pentaquarks, which have close relation to their inner structures. Both the $S$-$D$ wave mixing effect and the coupled channel effect are taken into account. We analyze the magnetic moments for the $S$-wave $Σ_c^{(*)}D^{(*)}$ molecular states, and extend our theoretical framework to study the transition magnetic moments and the radiative decay widths between the $S$-wave $Σ_c^{(*)}D^{(*)}$ molecules. We discuss the relations between the magnetic moments and the transition mag…
Baryons of the type Qqqqq-bar (where Q = c,b and q = u,d,s quarks) forming anti-decapenta (15)-plets with spin-parity one half-plus are predicted on simple theoretical considerations. The lightest members of these multiplets are explicitly exotic doublets cuuds-bar, cudds-bar with mass about 2420 MeV, and buuds-bar, budds-bar with mass about 5750 MeV, only 130 MeV heavier than Lambda_c and Lambda_b, respectively, and thus stable against strong decays. Although the production rate is probably very low, these remarkable pentaquarks can be looked for at LHC, Fermilab, B-factories, RHIC and elsewh…
Very recently, the LHCb Collaboration reported a fully charmed tetraquark state $X(6900)$ in the invariant mass spectrum of $J/ψ$ pairs. If one $J/ψ$ meson is replaced with a fully charmed baryon, we obtain a fully charmed pentaquark candidate. In this work, we perform a systematic study on the mass spectra of the S-wave fully heavy pentaquark $QQQQ\bar{Q}$ in the framework of the chromomagnetic interaction model. Based on our results in two different schemes, we further investigate the decay behaviors for them. We hope that our study will be helpful in searching for such types of exotic penta…
Hidden-charm pentaquark-like $P_{ψs}^Λ(4459)^0$ and $P_{ψs}^Λ(4338)$ resonances are studied in a constituent quark model as molecular meson-baryon structures. Such states are found in the $J^P(I)=\frac{1}{2}^-(0)$ channel with masses and widths compatible with the experimental measurements in a coupled-channels calculation with all the parameters constrained from previous studies. Other candidates are explored in the $J^P=\frac{1}{2}^-$, $\frac{3}{2}^-$ and $\frac{5}{2}^-$ channels in the charm and bottom sectors, with isospins $0$ ($P_{ψs}^Λ$ and $P_{Υs}^Λ$) and $1$ ($P_{ψs}^Σ$ and $P_{Υs}^Σ$…
LHCb recently announced the discovery of two exotic structures in the $J/ψ+ p$ decay channel, which have been referred to as charmonium-pentaquark states. Resolving between the models and clarifying the nature of the discovered hidden-charm pentaquark peaks, and possibly searching for similar peaks with other quantum numbers, requires further experimental studies. The states were observed in the decay mode $J/ψ+p$. Thus, it is natural to expect that these pentaquarks can be produced in the photoproduction process $γ+p\to P_c\to J/ψ+p$ where these states will appear as s-channel resonances at p…
A new interpretation of intrinsic charm phenomenon based on the assumption of pentaquark $\left| u u d c\bar{c} \right>$ mixing with a proton is offered. The structure function of the $c$-quark in the pentaquark is constructed. Mixing different states is considered theoretically and using experiment data on $D$-meson production and inclusive production of the hidden charm particles.
Recently, a new hidden-charm pentaquark state $P_{cs}(4459)$ was reported by the LHCb Collaboration. Stimulated by the fact that all hidden-charm pentaquark states in $S=0$ systems were successfully predicted by our chiral quark model, we extended this study to the $S=-1$ systems. All possible quantum numbers $IJ^P=0(\frac{1}{2})^-$, $0(\frac{3}{2})^-$, $0(\frac{5}{2})^-$, $1(\frac{1}{2})^-$, $1(\frac{3}{2})^-$ and $1(\frac{5}{2})^-$ have been investigated. The calculation results shows that the newly observed state $P_{cs}(4459)$ can be explained as $Ξ_c \bar{D}^*$ molecular state and the qua…
We study the hidden-charm pentaquark states $udsc\bar{c}$ with spins 1/2, 3/2, and 5/2 within the QCD sum-rule approach. First, we construct the currents for the particular configuration of pentaquark states that consist of the flavor singlet three-quark cluster $uds$ of spins 1/2 and 3/2 and the two-quark cluster $\bar cc$ of spin 1, where both clusters are in a color-octet state. From the QCD sum rules obtained by the operator product expansion up to dimension-10 condensates, the extracted masses for the pentaquark states $uds$-$\bar{c}c$ are about 4.6 GeV (5.6 GeV) for spin 1/2$^\pm$, about…
We develop an extension of the usual three flavor quark model to four flavors (u, d, s and c), and discuss the classification of pentaquark states with hidden charm. We fit our model to the known baryon spectrum and we predict the double and triple charm baryons, finding good agreement with the most recent lattice QCD calculations. We compute the the ground state of hidden charm pentaquarks and their associated magnetic moments and electromagnetic couplings, of interest to pentaquark photoproduction experiments.
We investigate the electromagnetic properties of possible charm-strange pentaquarks in the framework of the light-cone QCD sum rule using the photon distribution amplitudes. In particular, by calculating the corresponding electromagnetic form factors defining the radiative transitions under consideration we estimate the magnetic dipole and electric quadrupole moments of the pentaquark systems of a charm, an anti-strange and three light quarks. We observe that the values of magnetic dipole moments are considerably large, however, the quadrupole moments are very small. Any future measurements of…
We study one possible production mechanism for hidden charm pentaquark in e+e- collision, where it is produced via a color-octet c \bar c pair fragmentation. The pentaquark production at B factory energy is dominated by e+e- to c \bar c g to Pc + X. At Z^0 pole, for the pentaquark production, there are several partonic processes playing significant role. Our results show that it is possible to search for the direct pentaquark production signal at e+e- colliders, which is important to understand the properties of pentaquark.
The CLEO Collaboration recently has announced the discovery of an excited charmed and strange baryon. We estimate the expected width of this new member of the Xi_c family. We discuss the phenomenology of the excited csq and css states, and consider what additional charmed baryons might be observable in the future. We point out that the final state Xi_c + K could be an interesting new channel to examine.
Using the experimental data on pentaquarks with a hidden charm, new upper limits on the intrinsic charm in the proton are obtained, possible shapes of heavy quark distributions inside the proton are discussed.
We study a new nucleon resonance from eta photoproduction, which was observed at sqrt{s}=1675 MeV with a narrow decay width (~10 MeV) by the Tohoku LNS group as well as the GRAAL collaboration. Using an effective Lagrangian approach, we compute differential cross sections for the eta photoproduction. In addition to N*(1675,1/2+-,3/2+-), we employ six other nucleon resonances, i.e. N*(1520,1535,1650,1675,1710,1720) and vector meson exchanges which are the most relevant ones to this reaction process. As a result, we can reproduce the GRAAL data qualitatively well and observe obvious isospin asym…
We consider decays of the hidden charm LHCb pentaquarks in the hadrocharmonium and molecular scenarios. In both pictures the LHCb pentaquarks are essentially nonrelativistic bound states. We develop a semirelativistic framework for calculation of the partial decay widths that allows the final particles to be relativistic. Using this approach we calculate the decay widths in the hadrocharmonium and molecular pictures. Molecular hidden charm pentaquarks are constructed as loosely bound states of charmed and anticharmed hadrons. Calculations show that molecular pentaquarks decay predominantly int…
In this article, we restudy the ground state mass spectrum of the diquark-diquark-antiquark type $uudc\bar{c}$ pentaquark states with the QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of $13$ in a consistent way. The predicted masses support assigning the $P_c(4312)$ to be the hidden-charm pentaquark state with $J^{P}={\frac{1}{2}}^-$, assigning the $P_c(4440)$ to be the hidden-charm pentaquark state with $J^{P}={\frac{1}{2}}^-$, ${\frac{3}{2}}^-$ or ${\frac{5}{2}}^-$, assigning the $P_c(4457)$ to be the hidden-charm pentaquark state with $J^{P}={\fr…
We study the electroproduction of the LHCb pentaquark states with the assumption that they are resonant states. The main concern here is to investigate the final state distribution in the phase space in order to extract the feeble pentaquark signal from the large non-resonant background. Our results show that the ratio of the signal to background would increase significantly with proper kinematic cut, which would be very helpful for future experimental analysis.
Non-strange and strange pentaquaks with hidden charm are considered as diquark-diquark-antiquark composite systems. Spin and isospin content of such exotic states is discussed and masses are evaluated.
The LHCb collaboration have recently updated their analysis of the resonant $J/ψ\, p$ mass spectrum in the decay $Λ_b^0 \to J/ψ\, p\, K^-$, making use of their combined Run~1 and Run~2 data. In the updated analysis, three narrow states, $P_c (4312)^+$, $P_c (4440)^+$, and $P_c (4457)^+$, are observed. The spin-parity assignments of these states are not yet known. We interpret these narrow resonances as compact hidden-charm diquark-diquark-antiquark pentaquarks. Using an effective Hamiltonian, based on constituent quarks and diquarks, we calculate the pentaquark mass spectrum for the complete $…
We explore the possibility of observing the anti-charmed pentaquark state from the $Θ_c \bar{n} π^+$ decay of $B$ meson produced at $B$-factory experiments. We first show that the observed branching ratio of the $B^+$ to $ Λ^-_c p π^+$, as well as its open histograms, can be remarkably well explained by assuming that the decay proceeds first through the $π^+ \bar{D}^0$ (or $\bar{D}^{*0}$) decay, whose branching ratios are known, and then through the subsequent decay of the virtual $\bar{D}^0$ or $\bar{D}^{*0}$ mesons to $Λ_c^- p$, whose strength are calculated using previously fit hadronic par…
With the chiral quark model, we have calculated the axial charges of the pentaquark states with $(I,I_3)=(\frac{1}{2},\frac{1}{2})$ and $J^{P}=\frac{1}{2}^{\pm},\frac{3}{2}^{\pm},\frac{5}{2}^{\pm}$. The $P_c$ states with the same $J^P$ quantum numbers but different color-spin-flavor configurations have very different axial charges, which encode important information on their underlying structures. For some of the $J^{P}=\frac{3}{2}^{\pm}$ or $\frac{5}{2}^{\pm}$ pentaquark states, their axial charges are much smaller than that of the proton.
This paper calculates the magnetic moments of the hidden-charm strange pentaquark states with a quantum number of $J^P={\frac{1}{2}}^{\pm}$, ${\frac{3}{2}}^{\pm}$, ${\frac{5}{2}}^{\pm}$, and ${\frac{7}{2}}^{+}$ in the molecular, diquark-diquark-antiquark, and diquark-triquark models, respectively. Numerical results demonstrate that the magnetic moments change for a different spin-orbit coupling with the same model and when involving different models with the same angular momentum.
I develop an extension of the usual three-flavor quark model to four flavors (u, d, s and c), and discuss the classification of pentaquark states with hidden charm. This work is motivated by the recent observation of such states by the LHCb Collatoration at CERN.
In this work, we employ the light-cone QCD sum rule to calculate the magnetic dipole moments of the $P_c(4440)$, $P_c(4457)$ and $P_{cs}(4459)$ pentaquark states by considering them as the diquark-diquark-antiquark and molecular pictures with quantum numbers $J^P = \frac{3}{2}^-$, $J^P = \frac{1}{2}^-$ and $J^P = \frac{1}{2}^-$, respectively. In the analyses, we use the diquark-diquark-antiquark and molecular form of interpolating currents, and photon distribution amplitudes to obtain the magnetic dipole moment of pentaquark states. Theoretical examinations on magnetic dipole moments of the hi…
In the paper, we study the production of pentaquark $\bar{c}q qqq$ from singly bottom baryon. The tensor representations of pentaquark $\bar{c}q qqq$ are completed at first. Under the light quark symmetry analysis, we decompose the singly charmed pentaquarks into $6$, $15$ and $15'$ multiple states, and deduce the representations of these states. Then we construct the production Hamiltonian of the multiple states in proper order. For completeness, we systematically study the production channels of pentaquark states, including the possible production amplitudes and cross section relations betwe…
The mass spectrum of hidden charm pentaquark states composed of two diquarks and an antiquark are calculated by use of an effective Hamiltonian which includes explicitly the spin, color, and flavor dependent interactions. The results show that the $P_c(4312)^+$ and $P_c(4440)^+$ states could be explained as hidden charm pentaquark states with isospin and spin-parity $IJ^P=1/2\left(3/2^-\right)$, the $P_c(4457)^+$ state could be explained as a hidden charm pentaquark state with $IJ^P=1/2\left(5/2^-\right)$, and the $P_{cs}(4459)^+$ state could be explained as a hidden charm pentaquark state wit…
In a one-boson-exchange model, we study molecular states of double-charm baryon ($Ξ_{cc}(3621)$) and a charmed meson ($D$ and $D^*$). Our model indicates that there exist two possible triple-charm molecular pentaquarks, a $Ξ_{cc}D$ state with $I(J^P)=0(1/2^-)$ and a $Ξ_{cc}D^*$ state with $I(J^P)=0(3/2^-)$. In addition, we also extend our formula to explore $Ξ_{cc}\bar{B}^{(*)}$, $Ξ_{cc}\bar{D}^{(*)}$, and $Ξ_{cc}B^{(*)}$ systems, and find more possible heavy flavor molecular pentaquarks, a $Ξ_{cc}\bar{B}$ state with $I(J^P)=0(1/2^-)$, a $Ξ_{cc}\bar{B}^*$ state with $I(J^P)=0(3/2^-)$, and $Ξ_{…
The magnetic moment of a baryon state is an equally important dynamical observable as its mass, which encodes crucial information of its underlying structure. According to the different color-flavor structure, we have calculated the magnetic moments of the hidden-charm pentaquark states with $J^P={\frac{1}{2}}^{\pm}$, ${\frac{3}{2}}^{\pm}$, ${\frac{5}{2}}^{\pm}$ and ${\frac{7}{2}}^{+}$ in the molecular model, the diquark-triquark model and the diquark-diquark-antiquark model respectively. Although a good description for the pentaquark mass spectrum and decay patterns has been obtained in all t…
