arXiv subjects

Jia-Jun Wu

Publications and source records attributed to Jia-Jun Wu.

At least 37 records · Page 2Linked to original sources

arXiv2025

Finite Volume Hamiltonian method for two-particle systems containing long-range potential on the lattice

We propose a systematic method to block-diagonalize the finite volume effective Hamiltonian for two-particle systems with arbitrary spin in both the rest and moving frame. The framework is convenient and efficient for addressing the left-hand cut issue arising from long-range potential, which are challenging in the framework of standard Lüscher formula. Furthermore, the method provides a foundation for further extension to three-particle systems. We first benchmark our method by examining several toy models, demonstrating its consistency with standard Lüscher formula in the absence of long-range potential. In the presence of long-range potential, we investigate and resolve the effects and issues of left-hand cut. As a realistic application, we calculate the finite volume spectra of isoscalar $D\bar{D}^*$ system, where the well-known exotic state $χ_{c1}(3872)$ is observed. The results are qualitatively consistent with the lattice QCD calculation, highlighting the reliability and potential application of our framework to the study of other exotic states in hadron physics.

hep-lat↗

arXiv2025

Huizhou Hadron Spectrometer -- a Proposed High-rate Experimental Setup at the High Intensity Heavy-ion Accelerator Facility

The High-Intensity Heavy-Ion Accelerator Facility (HIAF), currently under construction in Huizhou, Guangdong Province, China, is projected to be completed by 2025. This facility will be capable of producing proton and heavy-ion beams with energies reaching several GeV, thereby offering a versatile platform for advanced fundamental physics research. Key scientific objectives include exploring physics beyond the Standard Model through the search for novel particles and interactions, testing fundamental symmetries, investigating exotic hadronic states such as di-baryons, pentaquark states and multi-strange hypernuclei, conducting precise measurements of hadron and hypernucleus properties, and probing the phase boundary and critical point of nuclear matter. To facilitate these investigations, we propose the development of a dedicated experimental apparatus at HIAF - the Huizhou Hadron Spectrometer (HHaS). This paper presents the conceptual design of HHaS, comprising a solenoid magnet, a five-dimensional silicon pixel tracker, a Low-Gain Avalanche Detector (LGAD) for time-of-flight measurements, and a Cherenkov-scintillation dual-readout electromagnetic calorimeter. The design anticipates an unprecedented event rate of 1-100 MHz, extensive particle acceptance, a track momentum resolution at 1% level, an electromagnetic energy resolution of ~3% @ 1 GeV and multi-particle identification capabilities. Such capabilities position HHaS as a powerful instrument for advancing experimental studies in particle and nuclear physics. The successful realization of HHaS is expected to significantly bolster the development of medium- and high-energy physics research within China.

hep-ex↗

arXiv2025

Unraveling $K(1690)$ as a pseudoscalar $ud\bar{d}\bar{s}$ tetraquark state

The recent observed $K (1690)$ has been identified as a supernumerary pseudoscalar resonance signal in the strange-meson spectrum predicted by quark model calculations. It is the best candidate of a strange crypto-exotic state. In this work, we systematically study the hadron masses of $ud\bar{d}\bar{s}$ tetraquark states with $J^P = 0^-$ in the method of QCD sum rules (QCDSR). For ten interpolating currents, we calculate the correlation functions up to dimension-8 nonperturbative condensates. To calculate the tri-gluon condensate, we comprehensively consider the contributions from different operators with and without covariant derivatives. The infrared (IR) safety can be guaranteed for the completely calculated tri-gluon condensate by properly addressing the IR divergences in Feynman diagrams. It is demonstrated that the tri-gluon condensate provides significant contributions to the sum-rule analyses in these light tetraquark systems. Our results support the interpretation of $K (1690)$ resonance to be a pseudoscalar $ud\bar{d}\bar{s}$ tetraquark state.

hep-ph↗

arXiv2025

High-Precision Physics Experiments at Huizhou Large-Scale Scientific Facilities

In response to the capabilities presented by the High-Intensity Heavy Ion Accelerator Facility (HIAF) and the Accelerator-Driven Subcritical System (CiADS), as well as the proposed Chinese Advanced Nuclear Physics Research Facility (CNUF), we are assembling a consortium of experts in relevant discipline--both domestically and internationally--to delineate high-precision physics experiments that leverage the state-of-the-art research environment afforded by CNUF. Our focus encompasses six primary domains of inquiry: hadron physics--including endeavors such as the super eta factory and investigations into light hadron structures; muon physics; neutrino physics; neutron physics; the testing of fundamental symmetries; and the exploration of quantum effects within nuclear physics, along with the utilization of vortex accelerators. We aim to foster a well-rounded portfolio of large, medium, and small-scale projects, thus unlocking new scientific avenues and optimizing the potential of the Huizhou large scientific facility. The aspiration for international leadership in scientific research will be a guiding principle in our strategic planning. This initiative will serve as a foundational reference for the Institute of Modern Physics in its strategic planning and goal-setting, ensuring alignment with its developmental objectives while striving to secure a competitive edge in technological advancement. Our ambition is to engage in substantive research within these realms of high-precision physics, to pursue groundbreaking discoveries, and to stimulate progress in China's nuclear physics landscape, positioning Huizhou as a preeminent global hub for advanced nuclear physics research.

hep-ph↗

arXiv2025

Resonance sum rules: an application to the square well potential

We propose an extension of the Quantum Chromodynamics (QCD) sum rules, termed the Resonance sum rules (RSR), to access resonance poles in the complex energy plane. By strategically introducing a contour in the complex plane and conformal mapping, the method intends to reach resonance poles on the second Riemann sheet. To validate this approach, we apply RSR to the square-well potential model, for which the pole locations are known. The analysis demonstrates a successful extraction of the pole positions and residues for both the $S$-wave and $P$-wave resonances. The results are in good agreement with the analytic solutions, with discrepancies within $5\%$ for the pole positions and $20\%$ for the residues.This framework provides a basis for future applications to realistic hadronic resonances, promising new insights into spectral properties of QCD.

hep-ph↗

arXiv2025

Two-photon production of $f_0$ and $a_0$ resonances as hadronic molecules composed of two vector mesons

Ascribed as $ρρ$ and $K^* \bar{K}^*$ molecular states, respectively, iso-scalar $f_0(1500)$ and $f_0(1710)$ states are expected to have iso-vector partners, potentially identified as $a_0(1450)$ and $a_0(1710)$. The predicted dominant decay modes for these two $a_0$ resonances are $a_0(1450) \to ωππ$ and $a_0(1710) \to ωππ,\,ϕππ$. We estimate cross sections for two-photon production of these four resonances within the hadronic molecular picture, and demonstrate that SuperKEKB's luminosity is sufficient for their observation and more precise parameter measurements.

hep-ph↗

arXiv2025

Modified Lüscher zeta-function and the modified effective range expansion in the presence of a long-range force

An efficient numerical algoritm is proposed for the calculation of the modified Lüscher zeta-function in the presence of a long-range force. Using the formalism developed in Ref.~\cite{Bubna:2024izx} for the analysis of synthetic data on the finite-volume energy levels in a toy model, it is demonstrated that, in contrast to the standard Lüscher approach, the truncation of the higher partial waves has very little effect on the final result. Furthermore, the regularization and renormalization of the modified Lüscher zeta-function is discussed in detail, as well as the problems arising within the cutoff regularization. It is shown that, using the renormalization scheme proposed in the present paper, one obtains modified effective range expansion parameters of natural size in all partial waves.

hep-lat↗

arXiv2025

Bottomonia in an unquenched quark model

The bottomonium spectrum is systematically studied within an unquenched quark model. Based on a good description of both the masses and widths for the well-established states, we further give predictions for the higher $S$-, $P$-, and $D$-wave bottomonium states up to a mass region of $\sim 11.3$ GeV. For the vector states, the $S$-$D$ mixing and dielectron decays are studied. Additionally, to understand the role of the higher vector resonances in the $e^{+}e^{-}$ annihilation reaction, we evaluate the cross section by combining our quark model predictions for the mass, dielectron and strong decay properties. It is found that (i) The mass shifts of the high $b\bar{b}$ states due to the coupled-channel effects are the order of a few tens MeV, most of the high-lying resonances contain significant non-$b\bar{b}$ components. (ii) The $Υ_1(3D,5D,6D)$ states significantly mix with $Υ(4S,6S,7S)$, respectively, which is mainly induced by the intermediate hadronic loops. (iii) The non-$b\bar{b}$ components will lead a significant suppression for the dielectron decay widths of some vector resonances.(iv) The threshold effects of open-bottom meson pairs can cause rich bump structures in the cross section of $e^{+}e^{-}\to b\bar{b}$. Our model shows that the $Υ(10753)$ may arise from threshold effects due to the strong coupling between $Υ(4S)$ and $\bar{B}^*B^*$.

hep-ph↗

arXiv2025

A radiative lepton model in a non-invertible fusion rule

We propose a new mechanism in which electron and muon masses are induced at one-loop level after dynamically violating the symmetry of the Ising fusion rule. In the neutrino sector, while the neutrino mass is generated at one-loop level, the Ising fusion rule plays a role in stabilizing the particles inside the loop. As a result, the symmetry works like a $Z_2$ symmetry that is not broken at any loop order. Subsequently, we discuss the lepton flavor violating processes, muon anomalous magnetic dipole moment, and relic density of dark matter, where we specify our dark matter candidate to be a singlet boson and briefly analyze the relic density by estimating the DM annihilation cross section. Finally, we present results for both the DM cross section and the muon $g-2$, satisfying the neutrino oscillation data as well as the constraints of lepton flavor violations.

hep-ph↗

arXiv2025

The Study of Pole Trajectory within a bare state in the coupled channel model

We investigate two-particle scattering and two-particle scattering with a bare basis state using Hamiltonian Effective Field Theory (HEFT). We analyze the distribution of two-body scattering poles in the momentum and energy planes under relativistic conditions. Compared to the non-relativistic case, there are significant differences in the distribution of bound state poles and resonance poles in the relativistic case, primarily due to the square root term in the relativistic formula. By considering pure two-particle scattering, we examine the relationship between the form factor and the number of poles. Additionally, we clearly elucidate the effects of attractive and repulsive interactions on the bound state poles and resonance poles. More importantly, we extend our model by including a bare state and explore the poles originating from the bare state or coupled channels through the trajectories of pole positions, as well as the compositeness of bound states.

hep-ph↗

arXiv2025

Investigation of box diagrams for the peak of $Z_{cs}(3985)$ in $e^+e^- \to D^-_s D^{0} K^+$ and $ D^{-}_s D^0 K^+$

The BESIII collaboration recently observed a charged hidden-charm structure with strangeness in the recoil mass spectrum of $K^+$ in the processes $e^+e^- \to D^-_s D^{*0} K^+$ or $D^{*-}_s D^0 K^+$, named as $Z_{cs}(3985)^-$. Within the energy region around the peak of $Z_{cs}(3985)$, various box diagrams are present. A systematic study of these box diagrams reveals the existence of a box singularity. Dalitz plots and invariant mass distributions of two charmed mesons from the box diagram for the processes $e^+e^- \to D^-_s D^{*0} K^+$ and $D^{*-}_s D^0 K^+$ are presented at five energy points $\sqrt s = 4.628,\,4.641,\,4.661,\,4.681$, and $4.698$ GeV. It is found that these box diagrams can generate peaks similar to those observed in experiments, suggesting that the peak of $Z_{cs}(3985)$ may be attributed to the box singularity contribution. Additionally, slight differences in the invariant mass spectra of $D^-_s D^{*0}$ and $D^{*-}_s D^0 K^+$ are identified based on the box diagrams, needing further experimental validation.

hep-ph↗

arXiv2025

Box Singularity Conditions in Box Diagrams of Decay Processes

Since 1959, singularities within single-loop diagrams have been studied. They are believed to significantly influence our understanding of experimental observables. In this study, we explore the singularities that arise from box diagrams in the decay process, which can be classified into two distinct categories. A comprehensive analysis of box singularities has been conducted, wherein we have derived and presented specific conditional formulae to ascertain the occurrence of singularities, along with the related physical scenarios.

hep-ph↗

arXiv2024

$P_c(4457)$ interpreted as a $J^P=1/2^+$ state by $\bar{D}^0Λ^+_c(2595)$-$π^0 P_c(4312)$ interaction

$P_c(4457)$ has been discovered over five years, but the parity of this particle remains undetermined. In this letter we propose a new interpretation for $P_c(4457)$, which is the state generated from the coupled-channel $\bar{D}^0Λ_c^{+}(2595)$ and $π^0 P_c(4312)$ since they can exchange an almost on-shell $Σ_c^+$. In this scenario, the parity of $P_c(4457)$ will be positive, which is different from the candidate of the bound state of $\bar{D}^*Σ_c$. The main decay channel of $P_c(4457)$ in this model is $P_c(4312)π$. We propose three processes $Λ_b^0 \to J/ψK_s p π^-$, $Λ_b^0 \to J/ψK^- p π^0$, and $Λ_b^0 \to J/ψp π^- π^+ K^-$ to verify $P_c(4457)\to P_c(4312)π$.

hep-ph↗

arXiv2024

How to unravel the nature of the $Σ^*(1430) (1/2^-)$ state from correlation functions

We calculate the correlation functions for the $\bar K^0 p, π^+ Σ^0, π^0 Σ^+, π^+ Λ$, and $ηΣ^+$ states, which in the chiral unitary approach predict an excited $Σ^*(1/2^-)$ state at the $\bar K N$ threshold, recently observed by the Belle Collaboration. Once this is done, we tackle the inverse problem of seeing how much information one can obtain from these correlation functions. With the resampling method, one can determine the scattering parameters of all the channels with relative precision by means of the analysis in a general framework, and find a clear cusplike structure corresponding to the $Σ^*(1/2^-)$ in the different amplitudes at the $\bar{K}N$ threshold.

hep-ph↗

arXiv2024

Production of exotic hadrons in $pp$ and nuclear collisions

Exotic hadrons beyond the conventional quark model have been discovered in the past two decades. Investigations of these states can lead to deep understanding of nonperturbative dynamics of the strong interaction. In this concise review, we focus on the productions of exotic hadrons in $pp$, $p\bar p$, and nuclear collisions. Experimental observations of light nuclei and hypernuclei, as prototypes of hadronic molecules, in heavy ion collisions will also be briefly discussed.

hep-ph↗

arXiv2024

Review of the low-lying excited baryons $Σ^*(1/2^-)$

Strong empirical and phenomenological indications exist for large sea-quark admixtures in the low-lying excited baryons. Investigating the low-lying excited baryon $Σ^*(1/2^-)$ is important to determine the nature of the low-lying excited baryons. We review the experimental and theoretical progress on the studies of the $Σ^*(1/2^-)$. Although several candidates have received intensive discussions, such as $Σ(1620)$ and $Σ(1480)$, their existence needs further confirmation. Following the prediction of the unquenched quark models for the $Σ^*(1/2^-)$, many theoretical works suggested the existence of these states in various processes. Future experimental measurements could shed light on the existence of the low-lying excited $Σ^*(1/2^-)$ state.

hep-ph↗

arXiv2024

Evidence of the low-lying baryon $Σ^*(1/2^-)$ in the process $Λ_c^+\to ηπ^+Λ$

Motivated by the Belle measurements of the process $Λ_c^+\to ηπ^+Λ$, we investigate this process by considering the contributions from the $Λ(1670)$, $a_0(980)$, and $Σ(1385)$. In addition, we also consider the predicted low-lying baryon $Σ^*(1/2^-)$. Our results involving the $Σ^*(1/2^-)$ are favored by fitting to the Belle data of the $ηΛ$ and $π^+Λ$ invariant mass distributions. Furthermore, we predict the $ηπ^+$ invariant mass distribution and the angular distribution $dΓ/d{\rm cos}θ$, which are significantly different depending on whether or not the contribution from the $Σ^*(1/2^-)$ is considered. Finally, we show that, with the contribution from the $Σ^*(1/2^-)$, the calculated Dalizt plot agrees with the Belle measurements. Future precise measurements of the process $Λ_c^+\to ηπ^+Λ$ could shed further light on the existence of the low-lying $Σ^*(1/2^-)$.

hep-ph↗

arXiv2024

A Three-Coupled-Channel Analysis of $Z_c(3900)$ Involving $D\bar{D}^*$, $πJ/ψ$, and $ρη_c $

In this work, we conduct a three-coupled-channel analysis of the $Z_c(3900)$ structure, focusing on the $D\bar{D}^*$, $J/ψπ$, and $ρη_c$ channels, based on the one-boson exchange model. Drawing from previous study on the exotic state $T_{cc}$, we only utilize one more parameter to construct the interactions between the channels. Our model successfully reproduces the experimental line shapes of the invariant mass distribution at $\sqrt{s} = 4.23$ and $4.26$ GeV for the three channels. Additionally, the finite-volume energy levels in our model show agreement with current LQCD conclusion. Detailed analysis suggests that the $Z_c(3900)$ peaks in the $πJ/ψ$ and $ρη_c$ distributions primarily arise from the triangle loop involving the $D_1 \bar{D} D^*$ intermediate system. In the $D\bar{D}^*$ distribution, the threshold peak is generated by the cascade decay mechanism enhanced by a triangle diagram. Moreover, we find a virtual pole located far from the threshold, indicating that $Z_c(3900)$ peaks are not associated with physical pole. We conclude that the $Z_c(3900)$ peaks are predominantly caused by the threshold cusp.

hep-ph↗