BESIII reports Born cross sections for e+e- to p pbar at 47 energies between 3.51 and 4.95 GeV and determines |GE/GM| and |GM| for the first time from angular distributions at large timelike momentum transfer.
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The hidden-charm pentaquark and tetraquark states
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abstract
In the past decade many charmonium-like states were observed experimentally. Especially those charged charmonium-like $Z_c$ states and bottomonium-like $Z_b$ states can not be accommodated within the naive quark model. These charged $Z_c$ states are good candidates of either the hidden-charm tetraquark states or molecules composed of a pair of charmed mesons. Recently, the LHCb Collaboration discovered two hidden-charm pentaquark states, which are also beyond the quark model. In this work, we review the current experimental progress and investigate various theoretical interpretations of these candidates of the multiquark states. We list the puzzles and theoretical challenges of these models when confronted with the experimental data. We also discuss possible future measurements which may distinguish the theoretical schemes on the underlying structures of the hidden-charm multiquark states.
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Explicit coupled-channel dynamics modifies pole structures and can eliminate or shift higher-lying states in doubly heavy systems, while single-channel models suffice only for near-threshold states like T_cc.
Chiral symmetry corrections in lattice QCD fits shift the D0*(2300) resonance pole closer to the Dπ threshold and reduce its width, while coupled channels produce a two-pole structure.
LCSR analysis of compact pentaquarks yields μ_u/μ_d = -2 for all currents and μ_c = 0 for one current, with numerical moments of order 1-3 μ_N that differ in flavor decomposition from molecular calculations.
QCD light-cone sum rules computation of magnetic dipole, electric quadrupole, and magnetic octupole moments for Σ-type P_ψs pentaquarks, with quark-flavor decomposition and model discriminants.
TQ4Q2.0 supplies the first complete, uncertainty-quantified set of NRQCD-based fragmentation functions for all-heavy tetraquarks, including nonconstituent channels and public grids for jet-associated production.
A radius-dependent chromoelectric interaction in the MIT bag model predicts that the state T_ncs̄n̄(0+, 2.925) is a compact tetraquark candidate corresponding to the experimentally observed T_c̄s0^a(2900).
Proposes that a K* Ξ molecular state (Λ(2150)) generates a triangle singularity explaining the peak in K- p → K Ξ(1530), with distinct spin density matrix element variations as a testable signature.
The M1 radiative decay width Pc(4457)(3/2-) → Pc(4312)(1/2-)γ is computed as 6.7 keV (range 2-9 keV) via 19 triangle loops with photon coupling to molecular components.
Neural-network quantum states are used to compute spectra of fully-heavy multiquarks in a non-relativistic quark model, claiming to overcome dimensionality issues with superior accuracy over prior approximations.
Joint Dalitz decomposition of two e+e- processes with dispersive pi pi / KKbar final-state interactions shows a non-resonant production term is required and extracts Breit-Wigner parameters for Zc(3900), Y(4220), and Y(4320).
A quark-diquark formalism extracts effective masses and couplings from known heavy baryon data to predict spectra across singly, doubly, and triply heavy sectors with two scenarios and a mass-dependent binding term.
Imposing the SU(3) flavor eigenstate condition on udsc c-bar pentaquarks in a constituent quark model yields two structures matching the masses of P_cs(4338) and P_cs(4459) plus two additional predicted states below the J/ψΛ threshold.
Born-Oppenheimer approximation calculations for doubly heavy hadrons match Gaussian expansion benchmarks at small heavy quark masses but diverge at larger masses, with Slater-type functions overestimating and Gaussian-type underestimating binding energies.
A multimodal, uncertainty-quantified set of leading-power fragmentation functions for all-charm pentaquarks is constructed and applied to NLL/NLO+ pentaquark-plus-jet production at future hadron colliders.
Joint analysis of experimental and lattice data confirms Z_c(3900) and Z_cs(3985) as SU(3) flavor partners with pole masses (3879.6 ± 4.8) MeV and (3976.9 ± 5.1) MeV, half-widths (32.2 ± 4.7) MeV and (28.8 ± 5.9) MeV, both resonances.
The DDK system supports a deeply bound compact state across wide parameters and possibly a shallow three-body halo state near the D-DK threshold, with negligible D*D*K coupling and no resonances.
Unquenched coupled-channel calculations yield sizable 2P–1F mixing angles of 7.5° and 15.4° for the χ_c2 charmonia, with predicted two-photon and two-gluon widths as experimental tests.
QCD sum rule analysis predicts the mass of a J^P=0^- compact hidden-charm hexaquark to be 3.94-4.41 GeV.
The DNN system forms a robust compact bound state in the I=1/2 (1^-) channel across cutoffs, while D*NN exhibits spin-dependent bound states in 0^-, 1^-, and 2^- channels with no resonances found.
Quark-exchange interactions at short distances dominate the coupled-channel scattering amplitudes for Zc(3900) over meson exchanges in an effective hadron-quark model.
QCD sum rules with local meson-meson currents for the K(1690) consistently predict masses around 2 GeV or above, disfavoring a molecular interpretation in favor of a compact multiquark state.
Using effective Lagrangians under molecular assumptions for η_c D* and J/ψ D*, the authors estimate B_c production branching ratios of 10^{-4} and 10^{-5} respectively, with decay widths O(MeV).
citing papers explorer
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Measurement of Born cross sections for $e^+e^-\to p\bar p$ at $\sqrt{s} =3.510-4.946$ GeV
BESIII reports Born cross sections for e+e- to p pbar at 47 energies between 3.51 and 4.95 GeV and determines |GE/GM| and |GM| for the first time from angular distributions at large timelike momentum transfer.
-
Systematic Study of Coupled-Channel Dynamics in Doubly Heavy Hadronic Molecules
Explicit coupled-channel dynamics modifies pole structures and can eliminate or shift higher-lying states in doubly heavy systems, while single-channel models suffice only for near-threshold states like T_cc.
-
Analysis of the $D_0^*(2300)$ resonance from lattice QCD under chiral symmetry
Chiral symmetry corrections in lattice QCD fits shift the D0*(2300) resonance pole closer to the Dπ threshold and reduce its width, while coupled channels produce a two-pole structure.
-
Analytic electromagnetic signatures of compact pentaquark structure: A multi-current QCD light-cone sum rules analysis of the $P_{\psi s}^{\Lambda}$ states
LCSR analysis of compact pentaquarks yields μ_u/μ_d = -2 for all currents and μ_c = 0 for one current, with numerical moments of order 1-3 μ_N that differ in flavor decomposition from molecular calculations.
-
Deciphering the nature of $P^{\Sigma}_{\psi s}$ pentaquarks in the light of their electromagnetic multipole moments
QCD light-cone sum rules computation of magnetic dipole, electric quadrupole, and magnetic octupole moments for Σ-type P_ψs pentaquarks, with quark-flavor decomposition and model discriminants.
-
All-charm tetraquarks at hadron colliders: A high-precision fragmentation perspective
TQ4Q2.0 supplies the first complete, uncertainty-quantified set of NRQCD-based fragmentation functions for all-heavy tetraquarks, including nonconstituent channels and public grids for jet-associated production.
-
Compactness, mass spectra, and strong stability of singly heavy tetraquarks
A radius-dependent chromoelectric interaction in the MIT bag model predicts that the state T_ncs̄n̄(0+, 2.925) is a compact tetraquark candidate corresponding to the experimentally observed T_c̄s0^a(2900).
-
Exploring $K\Xi^*$ and $K^*\Xi$ molecular states and the triangle singularity in the $K^- p \to K \Xi(1530)$ reaction
Proposes that a K* Ξ molecular state (Λ(2150)) generates a triangle singularity explaining the peak in K- p → K Ξ(1530), with distinct spin density matrix element variations as a testable signature.
-
Radiative decays of dynamically generated pentaquarks in the chiral unitary approach: the $P_c(4457)\to P_c(4312)\,\gamma$ transition
The M1 radiative decay width Pc(4457)(3/2-) → Pc(4312)(1/2-)γ is computed as 6.7 keV (range 2-9 keV) via 19 triangle loops with photon coupling to molecular components.
-
Fully-heavy multiquarks in neural-network quantum states
Neural-network quantum states are used to compute spectra of fully-heavy multiquarks in a non-relativistic quark model, claiming to overcome dimensionality issues with superior accuracy over prior approximations.
-
Simultaneous Dalitz-plot decomposition of the $e^+ e^- \to J/\psi \, \pi \, \pi \, (K \bar{K})$ processes in the 4.13-4.36 GeV region using dispersive final-state interactions
Joint Dalitz decomposition of two e+e- processes with dispersive pi pi / KKbar final-state interactions shows a non-resonant production term is required and extracts Breit-Wigner parameters for Zc(3900), Y(4220), and Y(4320).
-
Quark-diquark effective mass formalism for heavy baryon spectroscopy
A quark-diquark formalism extracts effective masses and couplings from known heavy baryon data to predict spectra across singly, doubly, and triply heavy sectors with two scenarios and a mass-dependent binding term.
-
Hidden-charm $uds\,c\bar c$ pentaquarks as flavor eigenstates in a constituent quark model
Imposing the SU(3) flavor eigenstate condition on udsc c-bar pentaquarks in a constituent quark model yields two structures matching the masses of P_cs(4338) and P_cs(4459) plus two additional predicted states below the J/ψΛ threshold.
-
Assessing the validity of the Born-Oppenheimer approximation in potential models for doubly heavy hadrons
Born-Oppenheimer approximation calculations for doubly heavy hadrons match Gaussian expansion benchmarks at small heavy quark masses but diverge at larger masses, with Slater-type functions overestimating and Gaussian-type underestimating binding energies.
-
Multimodal Fragmentation of All-Heavy Pentaquarks: Uncertainty-Aware Predictions for Hadron Colliders
A multimodal, uncertainty-quantified set of leading-power fragmentation functions for all-charm pentaquarks is constructed and applied to NLL/NLO+ pentaquark-plus-jet production at future hadron colliders.
-
Determination of the $Z_c(3900)$ and the $Z_{cs}(3985)$ states from joint analysis of experimental and lattice data
Joint analysis of experimental and lattice data confirms Z_c(3900) and Z_cs(3985) as SU(3) flavor partners with pole masses (3879.6 ± 4.8) MeV and (3976.9 ± 5.1) MeV, half-widths (32.2 ± 4.7) MeV and (28.8 ± 5.9) MeV, both resonances.
-
Coupled-channel study of the three-body $DDK$ and $D^{*}D^{*}K$
The DDK system supports a deeply bound compact state across wide parameters and possibly a shallow three-body halo state near the D-DK threshold, with negligible D*D*K coupling and no resonances.
-
Proposed mixing between $2P$ and $1F$ wave charmonia
Unquenched coupled-channel calculations yield sizable 2P–1F mixing angles of 7.5° and 15.4° for the χ_c2 charmonia, with predicted two-photon and two-gluon widths as experimental tests.
-
QCD Sum Rule Analysis of a Compact $D^{+}D^{-}K^{+}$-Like Hidden-Charm Hexaquark with $J^{P}=0^{-}$
QCD sum rule analysis predicts the mass of a J^P=0^- compact hidden-charm hexaquark to be 3.94-4.41 GeV.
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Three-body molecular states composed of $D^{(*)}$ and two nucleons
The DNN system forms a robust compact bound state in the I=1/2 (1^-) channel across cutoffs, while D*NN exhibits spin-dependent bound states in 0^-, 1^-, and 2^- channels with no resonances found.
-
$D\bar{D}^\ast$-$\pi J/\psi$ scatterings of coupled channels for $Z_c(3900)$ channel
Quark-exchange interactions at short distances dominate the coupled-channel scattering amplitudes for Zc(3900) over meson exchanges in an effective hadron-quark model.
-
QCD sum rule analysis of local meson-meson currents for the $K(1690)$ state
QCD sum rules with local meson-meson currents for the K(1690) consistently predict masses around 2 GeV or above, disfavoring a molecular interpretation in favor of a compact multiquark state.
-
Analysis of molecular state ${{\eta}_cD^*}$ and ${J/\psi D^*}$ in the effective Lagrangian approach
Using effective Lagrangians under molecular assumptions for η_c D* and J/ψ D*, the authors estimate B_c production branching ratios of 10^{-4} and 10^{-5} respectively, with decay widths O(MeV).