Critical Opalescence and Its Impact on the Jet Quenching Parameter q

Jet quenching parameter q is essential for characterizing the interaction strength between jet partons and nuclear matter.Based on the quark-meson model,we develop a new framework for calculating q at finite chemical potentials,in which q is related to the spectral function of the chiral order parameter.

Analysis of Strong Coupling Constant with Machine Learning and Its Application

We investigate the nature of the strong coupling constant and related physics.Through the analysis of accumulated experimental data around the world,we employ the ability of machine learning to unravel its physical laws.The result of our efforts is a formula that captures the expansive panorama of the distribution of the strong coupling constant across the entire energy range.

Two-Photon Exchange Corrections to Single Spin Asymmetry of Neutron and 3He

In a simple hadronie model, the two-photon exchange contributions to the single spin asymmetries for the nucleon and the 3He are estimated. The results show that the elastic contributions of two-photon exchange to the single spin asymmetries for the nucleon are rather small while those for the 3He are relatively large. Besides the strong angular dependence, the two-photon contributions to the single transfer. spin asymmetry for the 3He are very sensitive to the momentum

Perfect DD^(*) Molecular Prediction Matching the T_(cc) Observation at LHCb

In 2012,we investigated the possible molecular states composed of two charmed mesons[Phys.Rev.D 88(2013)114008;2012 arXiv:1211.5007[hep-ph]].The D^(*)D𝐷system with the quantum numbers of I(J^(P))=0(1^(+))was found to be a good candidate of the loosely bound molecular state.This state is very close to theD*D threshold with a binding energy around 0.47 MeV.This prediction was confirmed by the new LHCb observation of𝑇T^(+)_(cc)[see Franz Muheim’s talk at the European Physical Society conference on high energy physics 2021].

Four-charm-quark matter from the CMS collaboration as a witness of the development of high-precision Hadron spectroscopy

Twenty years have passed since the observation of the Xe3872Tas the first XYZ charmonium-like state.With the accumulation of experimental data,more and more new hadronic states have been discovered,inspiring extensive attention to exotic hadronic matter,including multiquarks,hybrid,and glueballs[1,2].Taking this opportunity,it is an appropriate time to build the“Particle Zoo2.0”version,which is the main task of the current study of hadron spectroscopy.More importantly,these joint experimental and theoretical efforts will further advance our understanding of the nonperturbative behavior of the strong interaction by these joint.In fact,representing the precision frontier of particle physics,hadron spectroscopy is entering the high-precision era.

Possible hidden-charm molecular baryons composed of an anti-charmed meson and a charmed baryon

Using the one-boson-exchange model,we studied the possible existence of very loosely bound hidden-charm molecular baryons composed of an anti-charmed meson and a charmed baryon.Our numerical results indicate that the Σ c ＊ and Σ c states exist,but that the Λ c and Λ c ＊ molecular states do not.

Possible strange hidden-charm pentaquarks from Σ_c^((*))_s~* and Ξ_c^((',*))~* interactions

Using the one-boson-exchange model, we investigate the Λcs^＊, Σcs^＊, Σc^＊s^＊, Ξc^＊, Ξ＇c^＊, and Ξc^＊^＊ interactions by considering the one-eta-exchange and/or one-pion-exchange contributions. We further predict the existence of hidden-charm molecular pentaquarks. Promising candidates for hidden-charm molecular pentaquarks include a Ξ＇cD^＊ state with 0（（1/2）^-） and the Ξc^＊D^＊ states with 0（1/2^-） and 0（3/2^-）. Experimental searches for these predicted hidden-charm molecular pentaquarks are an interesting future research topic for experiments like LHCb.

Interpretation of Z_b(10610) and Z_b(10650) in the ISPE mechanism and the Charmonium Counterpart

The initial single pion emission （ISPE） mechanism is applied to the processes r（5S）→πB（＊）B-（＊）, whose details have been recently reported at ICHEP2012, and we obtain reasonable agreement with Bell＇s measurements; that is, we succeed in reproducing the enhancement structures of Zb（10610） and Zb（10650）. Inspired by this success, we also predict the corresponding enhancement structures in open charm oue-pion decays of higher charmonia near the thresholds of D＊D- and D＊D-＊.

Photo-and electro-production of narrow exotic states:From light quarks to charm and up to bottom

Accessing a full image of the inner content of hadrons represents a central endeavour of modern particle physics,with the main scientific motivation to investigate the strong interaction binding the visible matter.On the one hand,the structure of known exotic candidates is a fundamental open issue addressed widely by scientists.On the other hand,looking for new states of exotic nature is a central component for theoretical and experimental efforts from electron-positron machine and electron accelerator with fixed target to heavy ion and electron-ion colliders.In this article we present a succinct short overview of the attempt to search for exotic narrow N∗and Z states containing light quarks only or also charm,and its connotation for bottom regions(the latter two are also known as Pc(Zc)and Pb(Zb)states,respectively in the literature).We address the effort of searching for exotic narrow N∗and Z states in light quark sector.We focus on recent progress in searching for signal of Pc and Zc states photoproduction and its implication into the Pb and Zb photoproduction and their decay properties.We also discuss future perspectives for the field in electron-ion colliders,a good place to disentangle the nature of some of these states and investigate some other enlightening topics including QCD trace anomaly and quarkonium-nucleon scattering length.

Nucleon resonances in πN→η'N and J/ψ→pη'

We are aiming to study the J/ψ →pqη′ decay in an isobar model and the effective Lagrangian approach on the basis of the coupling constants extracted from the πN→η′ reaction. After a careful exploration of the contributions of the S11（1535）, P11（1710）, P13（1900）, S11（2090） and Pl,（2100） resonances, we conclude that either a subthreshold resonance or a broad P-wave state in the near threshold range seems to be indispensable to describe the present data of the πN→η′.Furthermore, at least one broad resonance above rl＇N threshold is preferred. With this detailed analysis, we give the invariant mass spectrum and Dalitz plot of the J/ψ →pqη′decay for the purpose of assisting the future detailed partial wave analysis. It is found that the J/ψ →pqη′ data are useful for disentangling the above or below threshold resonant contribution, though it still further needs the differential cross section data of πN→η′ to realize some of the resonant and non-resonant contribution.

The Role of α1(1260) in π^-p→α1^-(1260)p and π^-p → π^-ρ^0p Reactions Near Threshold

We report on a theoretical study of the π^-→α1（1260）p and π^-→π^-~0p reactions near threshold within an effective Lagrangian approach.The production process is described by t-channel ρ^0 meson exchange.For the π^-→π^-ρ~0p reaction,the final π^-p^0 results from the decay of the α1（1260） resonance,which is assumed as a dynamically generated state from the K＊ K and ρπ coupled channel interactions.We calculate the total cross section of the π^-→α1（1260）p reaction.It is shown that,with the coupling constant of the α1（1260） to ρπ channel obtained from the chiral unitary theory and a cut off parameter Δρ～1.5 GeV in the form factors,the experimental measurement can be reproduced.Furthermore,the total and differential cross sections of π^p→α1（1260）p→π^ρ^0p reaction are evaluated,and it is expected that our model calculations can be tested by future experiments.These reactions are important for the study of the α1（1260） resonance and would provide further constraints on the properties of the α1（1260） state.

D*D1(2420)and D D'*(2600)interactions and the charged charmonium-like state Z(4430)

The D＊ D1（2420） and DD ＇＊（2600） interactions are studied in a one-boson-exchange model. Isovector bound state solutions with spin parity J^P= 1^＋are found from the D＊ D1（2420） interaction, which may be related to the observed charged charmonium-like state Z（4430）. There is no bound state solution found from the DD ＇＊（2600）interaction.

Discovery potentials of doubly charmed baryons

The existence of doubly heavy flavor baryons has not been well established experimentally so far. In this Letter we systematically investigate the weak decays of the doubly charmed baryons, Ξ;and Ξ;, which should be helpful for experimental searches for these particles. The long-distance contributions are first studied in the doubly heavy baryon decays, and found to be significantly enhanced. Comparing all the processes, Ξ;→Λ;K;π;π;andΞ;π;are the most favorable decay modes for experiments to search for doubly heavy baryons.

D^0-~0 mixing parameter y in the factorization-assisted topological-amplitude approach

We calculate theD^0-D^-0 mixing parameter y in the factorization-assisted topological-amplitude（FAT）approach, considering contributions from D^0→PP, PV, and VV modes, where P（V） stands for a pseudoscalar（vector） meson. The D^0→PP and PV decay amplitudes are extracted in the FAT approach, and the D^0→VV decay amplitudes with final states in the longitudinal polarization are estimated via the parameter set for D^0→PV. It is found that the VV contribution to y, being of order of 10-4, is negligible, and that the PP and PV contributions amount only up to y_（PP＋PV） =（0.21±0.07）%, a prediction more precise than those previously obtained in the literature,and much lower than the experimental data yexp =（0.61 ±0.08）%. We conclude that D^0 meson decays into other two-body and multi-particle final states are relevant to the evaluation of y, so it is difficult to understand it fully in an exclusive approach.

Estimating the production rates of D-wave charmed mesons via the semileptonic decays of bottom mesons

Using the covariant light-front approach with conventional vertex functions, we estimate the production rates of D-wave charmed/charmed-strange mesons via the B_((s)) semileptonic decays. As the calculated production rates are significant, it seems possible to experimentally search for D-wave charmed/charmed-strange mesons via semileptonic decays, which may provide an additional approach for exploring D-wave charmed/charmed-strange mesons.

Dipion decays of heavy baryons

Compared with the charmed baryons, the bottom baryons are not very well known, either experimentally Or theoretically. In this paper, we investigate the dipion strong decays of the P-wave and D-wave excited bottom baryons in the framework of the QPC model. We also extend the same analysis to the charmed baryons.

Photoproduction of hidden-charm states in the γp→D^(*0)Λ_c^+ reaction near threshold

We report on a theoretical study of the hidden charm N＊cc states in the γp→ D＊0∧＋c reaction near threshold within an effective Lagrangian approach. In addition to the contributions from the s-channel nucleon pole, the t-channel Do exchange, the u-channel A＋ exchange and the contact term, we study the contributions from the N＊cc states with spin-parity JP=1/2- and 3/2-. The total and differential cross sections of the γp→ D＊0∧＋c reaction are predicted. It is found that the contributions of these N＊cc states give clear peak structures in the total cross sections. Thus, this reaction is another new platform to study the hidden-charm states. It is expected that our model calculation may be tested by future experiments.

Doubly charmed dibaryon states

In this work,we study the doubly charmed dibaryon states with the qqqqcc(q=u,d,s)configuration.The mass spectra of doubly charmed dibaryon states are obtained systematically within the chromomagnetic interaction model.In addition to the mass spectrum analysis,we illustrate their two-body strong decay behaviours.Our results suggest that there may be narrow states or even stable states that cannot decay through the strong interaction.We hope that our results will provide valuable information for further experimental searches for doubly charmed dibaryon states.

Chiral corrections to the 1^-＋ exotic meson mass

We first construct the effective chiral Lagrangians tor the 1^-＋ exotic mesons.With the infrared regularization scheme,we derive the one-loop infrared singular chiral corrections to the π1（1600） mass explicitly.We investigate the variation of the different chiral corrections with the pion mass under two schemes.Hopefully,the explicit non-analytical chiral structures will be helpful for the chiral extrapolation of lattice data from the dynamical lattice QCD simulation of either the exotic light hybrid meson or the tetraquark state.

Double-heavy tetraquarks with strangeness in the chiral quark model

Recently,some progress has been made in the experiments on double-heavy tetraquarks,such as T_(cc)reported by the LHCb Collaboration and Xccssreported by the Belle Collaboration.Coming on the heels of our previous work about T_(cc) and T_(bb), we present a study on the bound and resonance states of their companions,QQqs(Q=c,b;q=u,s) tetraquarks with strange flavor in the chiral quark model.Two pictures,meson-meson and diquark-antidiquark ones,and their couplings were considered in our calculations.Isospin violation was neglected herein.Our numerical analysis indicated that the states ccus with 1/2(1^(+)) ald bbus with 1/2(1^(+)) are the most promising stable states against strong interactions.Besides,we found several resonance states for the double-heavy strange tetraquarks with the real scaling method.