arXiv subjects

Ya-Wen Pan

Publications and source records attributed to Ya-Wen Pan.

At least 19 recordsLinked to original sources

arXiv2026

Searching for the pseudoscalar partner of $G(3900)$ via radiative $Y(4230)$ decays

Inspired by the $P$-wave molecular interpretation of the recently observed vector state $G(3900)$, we analyze the production of its possible pseudoscalar partner, denoted here as $G_0(3900)$, via the radiative decay $Y(4230) \to \gamma G_0(3900)$. The $G_0(3900)$ is interpreted as a $P$-wave molecular state with quantum numbers $J^{PC}=0^{-+}$, dominated by the $D\bar{D}^{\ast}/\bar{D}D^{\ast}$ components. Although not yet experimentally established, such a structure is expected to appear near the $D\bar{D}^*$ threshold and to exhibit characteristic production patterns. The decay is assumed to proceed through a triangle mechanism. Depending on the model parameters and the binding energy of $G_0(3900)$, the resulting branching fraction lies in the range $\mathcal{B}(Y(4230) \to \gamma G_0(3900)) = 3.8 \times 10^{-5} - 3.3 \times 10^{-4}$. Our results offer a pathway to search for signatures of $G_0(3900)$ in radiative channels and also provide a test of the consistency of loop-mediated radiative decays with a molecular description of the $Y(4230)$.

hep-ph↗

arXiv2026

Probing the three-body force in hadronic systems with specific charge parity

Three-body forces, a type of non-perturbative strong interaction, are widely studied in nuclear physics. However, whether their inclusion is necessary in nuclear systems remains a topic of intense debate. In this letter, we propose that the existence of three-body forces in certain three-body hadronic systems with definite $C$-parity is certain. Such systems consist of two components whose interactions are mediated by three-body forces--a mechanism not easily realized in conventional three-nucleon systems. We investigate two specific three-body hadronic systems, $\bar{D}_sDK$ and $\bar{D}^*Dη$, using contact-range potentials. The two-body hadron-hadron interactions are constrained by reproducing their scattering lengths, while the three-body couplings are constrained by charge symmetry. Our results indicate that three-body forces play a minor role in binding the $I(J^{PC})=0(0^{--})$ $\bar{D}_sDK$ system, but a crucial one in binding the $I(J^{PC})=0(1^{-+})$ $\bar{D}^*Dη$ system. In fact, three-body forces determine whether $\bar{D} ^*Dη$ forms a bound state, making this system a promising candidate for exploring three-body forces in hadronic physics.

nucl-th↗

arXiv2025

Effect of a repulsive three-body interaction on the $DD^{(*)}K$ molecule

The hadronic molecular picture of the observed exotic states has inspired numerous investigations into few-body systems. Recently, the lattice effective field theory studied the effect of a three-body interaction on the binding energy of the $DD^{*}K$ system, revealing an intriguing phenomenon in the binding energy. This work uses the Gaussian expansion method to explore the underlying physics. Our results show that as the repulsive three-body interaction strengthens, the spatial size of the $DD^{(*)}K$ bound state gradually increases. Further enhancement of the three-body interaction causes the $DD^{(*)}K$ three-body bound state to break into a $D^{(*)}K$ two-body bound state, accompanied by a distant $D$ meson. The identical nature of the two $D$ mesons leads to the fact that the $DDK$ system consistently resembles an isosceles triangle-shaped spatial configuration.

nucl-th↗

arXiv2024

Three ways to decipher the nature of exotic hadrons: multiplets, three-body hadronic molecules, and correlation functions

In the past two decades, a plethora of hadronic states beyond the conventional quark model of $q\bar{q}$ mesons and $qqq$ baryons have been observed experimentally, which motivated extensive studies to understand their nature and the non-perturbative strong interaction. Since most of these exotic states are near the mass thresholds of a pair of conventional hadrons, the prevailing picture is that they are primarily hadronic molecules. In principle, one can verify the molecular nature of these states by thoroughly comparing their masses, decay widths, and production rates in a particular picture with experimental data. However, this is difficult or impossible. First, quantum mechanics allows for the mixing of configurations allowed by symmetries and quantum numbers. Second, data are relatively scarce because of their small production rates and the many difficulties in the experimental measurements. As a result, other alternatives need to be explored. This review summarizes three such approaches that can help disentangle the nature of the many exotic hadrons discovered. In the first approach, based on the molecular interpretations for some exotic states, we study the likely existence of multiplets of hadronic molecules related by various symmetries, such as isospin symmetry, SU(3)-flavor symmetry, heavy quark spin/flavor symmetry, and heavy antiquark diquark symmetry. In the second approach, starting from some hadronic molecular candidates, one can derive the underlying hadron-hadron interactions. With these interactions, one can study related three-body systems and check whether three-body bound states/resonances exist. In the third approach, one can turn to the femtoscopy technique to derive the hadron-hadron interactions, hence inaccessible. This technique provided an unprecedented opportunity to understand the interactions between unstable hadrons.

hep-ph↗

arXiv2024

Studying the heavy quark spin symmetry multiplet of hadronic molecules $\bar{D}^{()}Σ_c^{()}$ in the three-body decays of $\bar{D}^{(*)}Λ_c π$

The decay behavior of an exotic state can be used to probe its internal structure. We note that the hidden-charm pentaquark states, $P_ψ^{N}(4312)$, $P_ψ^{N}(4440)$, and $P_ψ^{N}(4457)$, have only been observed in the $J/ψp$ channel. In this work, we employ the effective Lagrangian approach to systematically investigate the two-body and three-body decays of the heavy quark spin symmetry multiplet of hadronic molecules $\bar{D}^{(*)}Σ_c^{(*)}$. Our results show that the partial decay widths of the hidden-charm pentaquark molecules into $\bar{D}^{(*)}Λ_c π$ are sizable so that $\bar{D}^{(*)}Λ_c π$ are promising channels to search for them, which can help clarify their molecular nature.

hep-ph↗

arXiv2024

Likely existence of bound states and the Efimov effect in the triple-$J/ψ$ system

The ground-breaking discovery of the first fully charmed tetraquark state $X(6900)$ in the $J/ψJ/ψ$ invariant mass distribution by the LHCb collaboration has inspired intensive theoretical studies. Various interpretations, such as molecular states, compact tetraquark states, and coupled-channel effects, have been proposed for these states. Of particular interest is the ongoing search for the triple-$J/ψ$ state--a fully-charmed hexaquark state. To deepen our understanding of the triple-$J/ψ$ state and to guide future experimental searches, we study the triple-$J/ψ$ system in this work employing the Gaussian expansion method and the $J/ψJ/ψ$ potential parameterized to yield a shallow bound state, as suggested in several theoretical works. Our results support a triple-$J/ψ$ bound state, even in cases where the attractive interaction between the two $J/ψ$ mesons is very weak. Moreover, our analysis implies the Efimov effect in the triple-$J/ψ$ system. In addition, we extend our investigation to the triple-$Υ(1S)$ system and obtain results similar to those for the triple-$J/ψ$ system.

hep-ph↗

arXiv2023

Systematic studies of $DDKK$ and $D\bar{D}K\bar{K}$ four-hadron molecules

Assuming that $D_{s0}^{*}(2317)$ is a $DK$ molecular state with a binding energy of 45 MeV, we investigate the existence of four-hadron molecules, $DDKK$ and $D\Bar{D}K\Bar{K}$, with the Gaussian expansion method. Their binding energies are $138\sim155$ MeV and $123\sim163$ MeV below the mass thresholds of $DDKK$ and $D\Bar{D}K\Bar{K}$. The $D\Bar{D}K\Bar{K}$ state has a decay width of $36\sim54$ MeV due to the complex $K\Bar{K}$ interaction. Further theoretical studies of and experimental searches for such four-hadron molecules can help deepen the understanding of the nonperturbative strong interaction in a nontrivial way.

hep-ph↗

arXiv2023

Production rates of hidden-charm pentaquark molecules in $Λ_b$ decays

The partial decay widths and production mechanism of the three pentaquark states, $P_ψ^{N}(4312)$, $P_ψ^{N}(4440)$, and $P_ψ^{N}(4457)$, discovered by the LHCb Collaboration in 2019, are still under debate. In this work, we employ the contact-range effective field theory approach to construct the $\bar{D}^{(*)}Σ_{c}^{(*)}$, $\bar{D}^{*}Λ_c$, $\bar{D}Λ_c$, $J/ψp$, and $η_c p$ coupled-channel interactions to dynamically generate the multiplet of hidde-charm pentaquark molecules by reproducing the masses and widths of $P_ψ^{N}(4312)$, $P_ψ^{N}(4440)$, and $P_ψ^{N}(4457)$. Assuming that the pentaquark molecules are produced in the $Λ_b$ decay via the triangle diagrams, where $Λ_{b}$ firstly decays into $D_{s}^{(\ast)}Λ_{c}$, then $D_{s}^{(\ast)}$ scatters into $\bar{D}^{(\ast)}K$, and finally the molecules are dynamically generated by the $\bar{D}^{(\ast)}Λ_{c}$ interactions, we calculate the branching fractions of the decays $Λ_b \to {P_ψ^{N}}K$ using the effective Lagrangian approach. With the partial decay widths of these pentaquark molecules, we further estimate the branching fraction of the decays $ Λ_b \to ( P_ψ^{N} \to J/ψp )K $ and $ Λ_b \to ( P_ψ^{N}\to \bar{D}^* Λ_c )K $. Our results show that the pentaquark states $P_ψ^{N}(4312)$, $P_ψ^{N}(4440)$, and $P_ψ^{N}(4457)$ as hadronic molecules can be produced in the $Λ_b$ decay, and on the other hand their heavy quark spin symmetry partners are invisible in the $J/ψp$ invariant mass distribution because of the small production rates. Our studies show that is possible to observe some of the pentaquark states in the $Λ_b\to \bar{D}^*Λ_c K$ decays.

hep-ph↗

arXiv2022

Five-flavor pentaquarks and other light- and heavy-flavor symmetry partners of the LHCb hidden-charm pentaquark

The discovery of three pentaquark peaks -- the $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$ -- by the LHCb collaboration has a series of interesting consequences for hadron spectroscopy. If these hidden-charm objects are indeed hadronic molecules, as suspected, they will be constrained by heavy-flavor and SU(3)-flavor symmetries. The combination of these two symmetries will imply the existence of a series of five-flavor pentaquarks with quark content $\bar{b} c s d u$ and $b \bar{c} s d u$, that is, pentaquarks that contain each of the five quark flavors that hadronize. In addition, from SU(3)-flavor symmetry alone we expect the existence of light-flavor partners of the three $P_c$ pentaquarks with strangeness $S=-1$ and $S=-2$. The resulting structure for the molecular pentaquarks is analogous to the light-baryon octet -- we can label the pentaquarks as $P_{Q' \bar{Q}}^N$, $P_{Q' \bar{Q}}^Λ$, $P_{Q' \bar{Q}}^Σ$, $P_{Q' \bar{Q}}^Ξ$ depending on their heavy- and light-quark content (with $N$, $Λ$, $Σ$, $Ξ$ the member of the light-baryon octet to which the light-quark structure resembles and $Q'$, $\bar Q$ the heavy quark-antiquark pair). In total we predict $45$ new pentaquarks from heavy- and light-flavor symmetries alone, which extend up to $109$ undiscovered states if we also consider heavy-quark spin symmetry. If an isoquartet ($I={3/2}$) hidden-charm pentaquark is ever observed, this will in turn imply a second multiplet structure resembling the light-baryon decuplet: $P_{Q' \bar{Q}}^Δ$, $P_{Q' \bar{Q}}^{Σ^*}$, $P_{Q' \bar{Q}}^{Ξ^*}$, $P_{Q' \bar{Q}}^Ω$.

hep-ph↗

arXiv2022

Hadronic molecules composed of a doubly charmed tetraquark state and a charmed meson

The three pentaquark states, $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$, discovered by the LHCb Collaboration in 2019, can be arranged into a complete heavy quark spin symmetry multiplet of hadronic molecules of $\bar{D}^{(\ast)}Σ_{c}^{(\ast)}$. In the heavy quark mass limit, the $Σ_{c}^{(\ast)}$ baryons can be related to the doubly charmed tetraquark states of isospin 1, i.e., $T_{\bar{c}\bar{c}}^{(\ast)}$( $T_{\bar{c}\bar{c}}^{0}$, $T_{\bar{c}\bar{c}}^{1}$, $T_{\bar{c}\bar{c}}^{2}$), via heavy antiquark diquark symmetry, which dictates that the $\bar{D}^{(\ast)}Σ_{c}^{(\ast)}$ interactions are the same as the $\bar{D}^{(\ast)}T_{\bar{c}\bar{c}}^{(\ast)}$ interactions up to { heavy antiquark diquark symmetry} breakings. In this work, we employ the contact-range effective field theory to systematically study the $\bar{D}^{(\ast)}T_{\bar{c}\bar{c}}^{(\ast)}$ systems, and we show the existence of a complete heavy quark spin symmetry multiplet of hadronic molecules composed of a doubly charmed tetraquark state and a charmed meson. These are a new kind of hadronic molecules and, if discovered, can lead to a better understanding of the many exotic hadrons discovered so far. In addition, we summarise the triply charmed hexaquark states formed by different combinations of hadrons. In particular, we show that $\barΩ_{ccc}{p}$ system can bind by the Coulomb force, which is analogous to a hydrogenlike atom.

hep-ph↗

arXiv2022

Multi-hadron molecules: status and prospect

Starting from 2003, the discovery of a large amount of the so-called exotic hadronic states, i.e., the $XYZ$ states, the pentaquark states as well as the tetraquark states, have not only revived studies of hadron spectroscopy, but also hinted at the existence of new multi-hadron states made of hadrons other than nucleons and hyperons. We briefly comment on some of the latest studies on multi-hadron molecules in the light and heavy flavor sectors and highlight what should be done in the future.

hep-ph↗

arXiv2022

Three-body molecules $\bar{D}\bar{D}^{\ast}Σ_{c}$- understanding the nature of $T_{cc}$, $P_{c}(4312)$, $P_{c}(4440)$ and $P_{c}(4457)$

The nature of the three pentaquark states, $P_{c}(4312)$, $P_{c}(4440)$ and $P_{c}(4457)$, discovered by the LHCb Collaboration in 2019, is still under debate, although the $\bar{D}^{(\ast)}Σ_{c}$ molecular interpretation seems to be the most popular. In this work, by adding a $\bar{D}$ meson into the $\bar{D}^{\ast}Σ_{c}$ pair, we investigate the mass and decay width of the three-body molecules $\bar{D}\bar{D}^{\ast}Σ_{c}$ and explore the correlation between the existence of the $\bar{D}\bar{D}^{\ast}Σ_{c}$ molecules with the existence of $\bar{D}^{(\ast)}Σ_{c}$ and $\bar{D}^{\ast}\bar{D}$ two-body molecules. The latter can be identified with the doubly charmed tetraquark state $T_{cc}$ recently discovered by the LHCb Collaboration. Based on the molecular nature of $P_{c}(4312)$, $P_{c}(4440)$, $P_{c}(4457)$, and $T_{cc}$, our results indicate that there exist two three-body bound states of $\bar{D}\bar{D}^{\ast}Σ_{c}$ with $I(J^{P})=1(1/2^{+})$ and $I(J^{P})=1(3/2^{+})$, and binding energies $37.24$ MeV and $29.63$ MeV below the $\bar{D}\bar{D}^{\ast}Σ_{c}$ mass threshold. In addition, we find that the mass splitting of these two three-body molecules are correlated to the mass splitting of $P_{c}(4440)$ and $P_{c}(4457)$, which offers a non-trivial way to reveal the molecular nature of these states. The partial widths of two $\bar{D}\bar{D}^{\ast}Σ_{c}$ molecules decaying into $J/ψp \bar{D}$ and $J/ψp \bar{D}^{\ast}$ are found to be several MeV. We recommend the experimental searches for the $\bar{D}\bar{D}^{\ast}Σ_{c}$ molecules in the $J/ψp \bar{D}$ and $J/ψp \bar{D}^{\ast}$ invariant mass distributions.

hep-ph↗

arXiv2021

Discovery of the doubly charmed $T_{cc}^+$ state implies a triply charmed $H_{ccc}$ hexaquark state

The doubly charmed exotic state $T_{cc}$ recently discovered by the LHCb Collaboration could well be a $DD^{*}$ molecular state long predicted in various theoretical models, in particular, the $DD^*$ isoscalar axial vector molecular state predicted in the one-boson-exchange model. In this work, we study the $DDD^*$ system in the Gaussian Expansion Method with the $DD^*$ interaction derived from the one-boson-exchange model and constrained by the precise binding energy of $273\pm63$ keV of $T_{cc}$ with respect to the $D^{*+}D^0$ threshold. We show the existence of a $DDD^*$ state with a binding energy of a few hundred keV and spin-parity $1^-$. Its main decay modes are $DDDπ$ and $DDDγ$. The existence of such a state could in principle be confirmed with the upcoming LHC data and will unambiguously determine the nature of the $T_{cc}^+$ state and of the many exotic state of similar kind, thus deepening our understanding of the non-perturbative strong interaction.

hep-ph↗

arXiv2021

Hidden charm pentaquark with strangeness $P_{cs}^*(4739)$ as a $Σ_{c}\bar{D}\bar{K}$ bound state

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 using the Gaussian Expansion Method, which can be viewed as an excited hidden charm pentaquark state with strangeness, $P_{cs}^*(4739)$, with $I(J^P)=1(1/2^+)$ and a binding energy of $77.8^{+25}_{-10.3}$ MeV. We further study its strong decays via triangle diagrams and show that its partial decay widths into $DΞ_c'$ and $D_s^*Σ_c$ are of a few ten's MeV, with the former being dominant.

hep-ph↗

arXiv2021

Triply charmed dibaryons in the one boson exchange model

The pentaquark states, $P_{c}(4312)$, $P_{c}(4440)$ and $P_{c}(4450)$, can be nicely arranged into a multiplet of seven molecules of $\bar{D}^{(\ast)}Σ_{c}^{(\ast)}$ dictated by heavy quark spin symmetry, while the $Ξ_{cc}^{(\ast)}Σ_{c}^{(\ast)}$ system can be related to the $\bar{D}^{(\ast)}Σ_{c}^{(\ast)}$ system via heavy antiquark diquark symmetry. In this work we employ the one boson exchange model to study the interactions between $Ξ_{cc}^{(\ast)}$ and $Σ_{c}^{(\ast)}$ with constraints from the pentaquark system. We show that a multiplet of ten triply charmed dibaryons emerge naturally in the isospin-1/2 sector, while only three appear in the isospin-3/2 sector. In addition, we study their heavy quark flavor partners. Ten triply bottom diybaryons are found in the isospin-1/2 sector, while only nine are likely in the isospin-3/2 sector. Furthermore, the predicted mass splitting between the $0^{+}$ $Ξ_{cc}Σ_{c}$ state and its $1^{+}$ counterpart is found to be consistent with the correlation implied by heavy antiquark diquark symmetry recently pointed out in Pan $et$ $al$..

hep-ph↗

arXiv2020

Can discovery of hidden charm strange pentaquark states help determine the spins of $P_c(4440)$ and $P_c(4457)$?

The pentaquark states, $P_{c}(4312)$, $P_{c}(4440)$ and $P_{c}(4457)$, could be nicely arranged into a multiplet of seven molecules of $\bar{D}^{(\ast)}Σ_{c}^{(\ast)}$ dictated by heavy quark spin symmetry. However, the spins of $P_c(4440)$ and $P_c(4457)$ are not yet fully determined. In this work we employ the contact-range effective field theory to investigate the $SU(3)$-flavor counterparts of $\bar{D}^{(\ast)}Σ_{c}^{(\ast)}$, and study the possibility whether their discovery can help determine the spins of $P_c(4457)$ and $P_c(4440)$. We find the existence of a complete hidden charm strange multiplet of $\bar{D}^{(\ast)}Ξ_{c}^{(\prime\ast)}$ molecules irrespective of the spins of $P_c(4440)$ and $P_c(4457)$. On the other hand, we find that although molecules of $\bar{D}^{(\ast)}Ξ_{c}$ are also likely, depending on the realization of the underlying dynamics, their discovery can be more useful to determine the spins of $P_{c}(4440)$ and $P_{c}(4457)$ and to tell how the heavy quark and light quark interaction depends on the spin of the light quark pair.

hep-ph↗

arXiv2019

Strong decays of the explicitly exotic doubly charmed $DDK$ bound state

Nowadays, it is generally accepted that the $DK$ interaction in isospin zero is strongly attractive and the $D_{s0}^*(2317)$ can be described as a $DK$ molecular state. Recent studies show that the three-body $DDK$ system binds as well with a binding energy about 60$\sim$70 MeV. The $DDK$ bound state has isospin $1/2$ and spin-parity $0^-$. If discovered either experimentally or in lattice QCD, it will not only provide further support on the molecular nature of the $D_{s0}^*(2317)$, but also provide a way to understand other exotic hadrons expected to be of molecular nature. In the present work, we study its two-body strong decay widths via triangle diagrams. We find that the partial decay width into $DD_sπ$ is at the order of $2\sim3$ MeV, which seems to be within the reach of the current experiments such as BelleII. As a result, we strongly recommend this decay channel of the $DDK$ bound state to be searched for experimentally.

hep-ph↗

arXiv2019

Model independent determination of the spins of the $P_{c}$(4440) and $P_{c}$(4457) from the spectroscopy of the triply charmed dibaryons

The LHCb collaboration has recently observed three narrow pentaquark states --- the $P_c(4312)$, $P_c(4440)$, and $P_c(4457)$ ---that are located close to the $\bar{D} Σ_c$ and $\bar{D}^* Σ_c$ thresholds. Among the so-far proposed theoretical interpretations for these pentaquarks, the molecular hypothesis seems to be the preferred one. Nevertheless, in the molecular picture the spins of the $P_c(4440)$ and $P_c(4457)$ have not been unambiguously determined yet. In this letter we point out that heavy antiquark-diquark symmetry induces a model-independent relation between the spin-splitting in the masses of the $P_c(4440)$ and $P_c(4457)$ $\bar{D}^* Σ_c$ pentaquarks and the corresponding splitting for the $0^+$ and $1^+$ $Ξ_{cc} Σ_c$ triply charmed dibaryons. This is particularly relevant owing to a recent lattice QCD prediction of the $1^+$ triply charmed dibaryon, which suggests that a calculation of the mass of its $0^+$ partner might be within reach. This in turn would reveal the spins of the $P_c(4440)$ and $P_c(4457)$ pentaquarks, providing a highly nontrivial test of heavy-quark symmetry and the molecular nature of the pentaquarks. Furthermore, the molecular interpretation of the hidden-charm pentaquarks implies the existence of a total of ten triply charmed dibaryons as $Ξ_{cc}^{(*)} Σ_c^{(*)}$ molecules, which, if confirmed in the lattice, will largely expand our understanding of the non-perturbative strong interaction in the heavy-quark sector.

hep-ph↗