The transverse single-spin asymmetry forρ^(0) production in semi-inclusive deep inelastic scattering was recently reported by the COMPASS Collaboration.Using the Sivers function extracted from pion and kaon productio...The transverse single-spin asymmetry forρ^(0) production in semi-inclusive deep inelastic scattering was recently reported by the COMPASS Collaboration.Using the Sivers function extracted from pion and kaon productions,we perform a calculation of the Sivers asymmetry within the transverse momentum-dependent factorization.Our results are consistent with the COMPASS data,supporting the universality of the Sivers function in the semi-inclusive deep inelastic scattering process for different final-state hadrons within current experimental uncertainties.While different parametrizations of the Sivers function from global analyses allow describing the data equally well,we obtain very different predictions on the Sivers asymmetry ofρand K^(*)productions at electron-ion colliders,which therefore are expected to provide further constraints.展开更多
Based on the quark-gluon contents of nucleon and strongly believing that the force mediators,Pomeronand its counterpart in the conventional approach of Regge theory,for high energy diffractive process would be the ten...Based on the quark-gluon contents of nucleon and strongly believing that the force mediators,Pomeronand its counterpart in the conventional approach of Regge theory,for high energy diffractive process would be the tensorglueball and Odderon respectively,we discuss photo-production of vector meson φ off the deuteron at energy less than 3GeV in the QCD inspired model in which the quark gluon degrees of freedom and glueball,Odderon exchange are takeninto account.A calculation is performed for γ + D →φ + D,and the theoretical predictions of the differential crosssection dσ^(γD)) /dt,are presented and compared with available experimental data.Our QCD inspired model reproducesdata quite well in the whole range of the experimental measurements up to |t| ■0.4 GeV.Our results can be used toextract γn→φn data,which cannot be measured in experiment.展开更多
Based on Pomeron exchange model, elastic production of vector meson in electro-proton interaction is investigated with both linear and non-linear Pomeron trajectory. A numerical calculation for J/psi production is per...Based on Pomeron exchange model, elastic production of vector meson in electro-proton interaction is investigated with both linear and non-linear Pomeron trajectory. A numerical calculation for J/psi production is performed. The effect of the energy scale so and photon virtuality Q(2) on differential cross section are also predicted. A good agreement with experimental data is obtained. Our conclusions are that the Pomeron exchange model is a successful description of J/psi electro-production, the dependence of the differential cross sections on Q2 is negligible, the linear trajectory is a good approximation to non-linearity of the Pomeron trajectory, and the value of the energy scale parameter so is dependent on the momentum transfer, namely its effect is moderate at low momentum transfer but it causes no difference at high momentum transfer vertical bar t vertical bar >= 1.25 GeV2.展开更多
Vector meson mass values are studied at finite chemical potential and temperature in lattice QCD with lattice size of 24 × 122× 6 using two flavors of staggered quarks. The investigation focuses on the chang...Vector meson mass values are studied at finite chemical potential and temperature in lattice QCD with lattice size of 24 × 122× 6 using two flavors of staggered quarks. The investigation focuses on the change of the vector meson mass in the critical region close to T c with two different types of chemical potentials switched on: the isoscalar chemical potential μS and its isovector counterpart μV. It is found that the vector meson mass increases in the QGP phase with both chemical potentials and decreases with μS in the confinement phase.展开更多
In this article,we study the vector meson transitions among the charmonium and bottomonium states with the heavy quark effective theory in a systematic way,and make predictions for the ratios among the vector meson de...In this article,we study the vector meson transitions among the charmonium and bottomonium states with the heavy quark effective theory in a systematic way,and make predictions for the ratios among the vector meson decay widths of a special multiplet to another multiplet.The predictions can be confronted with the experimental data in the future.展开更多
Low-mass vector meson(ρ, ω, and Ф) production at forward rapidity in p+p and d+Au collisions at (~SNN)^(1/2)=200 Ge V is studied within the framework of a multiphase transport model(AMPT). Detailed investigations, ...Low-mass vector meson(ρ, ω, and Ф) production at forward rapidity in p+p and d+Au collisions at (~SNN)^(1/2)=200 Ge V is studied within the framework of a multiphase transport model(AMPT). Detailed investigations, including the transverse momentum and the rapidity dependence of low-mass vector meson production in the AMPT model, show that the hadron interaction process is important for a quantitative description of the ρ and ω data.But for the Ф meson, the strange quark production in the AMPT model with the string melting scenario describes the data reasonably well, while the default AMPT model under-predicts the data. The N(Ф)=N(ρ+ω) ratio from the AMPT model with the string melting scenario perfectly describes the data in p+p collisions. For the d+Au collisions, an increased trend of this ratio vs. transverse momentum and the number of participants are observed from the AMPT model. Our results indicate that a precise measurement of the N(Ф)=N(ρ+ω) ratio in d+Au and Au+Au collisions will shed more light on the strangeness production and its dynamics in quark–gluon plasma.展开更多
We calculate inclusive light vector mesons(ρ,ω,and φ) production in relativistic heavy ion collisions based on the idea of gluon saturation in the color glass condensate(CGC) framework.At high energies,the value of...We calculate inclusive light vector mesons(ρ,ω,and φ) production in relativistic heavy ion collisions based on the idea of gluon saturation in the color glass condensate(CGC) framework.At high energies,the value of saturation momentum becomes larger than the Quantum Chromodynamics(QCD) confinement scale ∧_(QCD),which implies thatα_s(Q_s) <<1.Using the relativistic kinetic theory,we derive the production rate for the light vector mesons produced by gluon-gluon fusion in the k_T-factorization approach.The numerical results indicate that the light vector mesons from the color glass condensate become prominent in p-p,p-Pb,and Pb-Pb collisions at Large Hadron Collider(LHC) energies.展开更多
Radiative decay of heavy ground state vector meson V → Pγis treated semi-classically in the scalar strong interaction hadron theory. The treatment successfully employs the new wave function of the vector me...Radiative decay of heavy ground state vector meson V → Pγis treated semi-classically in the scalar strong interaction hadron theory. The treatment successfully employs the new wave function of the vector meson updated here. The ratio of the available J/ψ and decay rates agrees with prediction. The values of the predicted rates are also in order of magnitude agreement with measurements. These agreements are the only ones directly computed from a first principles’ theory.展开更多
In this paper,a formalism is presented for the helicity amplitude analysis of the decays Ψ(2S)→γ_(1)χ_(c)J,χ_(c)J→γ_(2)V(V=p^(0),φ,ω)(subscripts 1 and 2 are used to distinguish the two radiative photons),and ...In this paper,a formalism is presented for the helicity amplitude analysis of the decays Ψ(2S)→γ_(1)χ_(c)J,χ_(c)J→γ_(2)V(V=p^(0),φ,ω)(subscripts 1 and 2 are used to distinguish the two radiative photons),and the polarization expressions of the P-wave charmonia χ_(c)J and the vector mesons p^(0),φ,ω for experimental measurements at an electron-positron collider.In addition,we derive formulae for the angular distributions of χ_(c1,2)→γV to extract the degree of transverse polarization P_(T) of e^(+)e^(-)pairs with symmetric beam energy as well as the ratios of two helicity amplitudes x(in χ_(c1) decays)and x,y(in χ_(c2) decays),which represent the relative magnitudes of transverse to longitudinal polarization amplitude.The results are validated by Monte Carlo simulation.Finally,the statistical sensitivity of P_(T),x,and y are estimated based on the large Ψ(2S)data samples collected at current and proposed future e^(+)e^(-)colliderexperiments.展开更多
The global spin alignment of vector mesons has been observed by the STAR collaboration at the Relativistic Heavy Ion Collider(RHIC)at Brookhaven National Laboratory(BNL).It provides a unique opportunity to probe the c...The global spin alignment of vector mesons has been observed by the STAR collaboration at the Relativistic Heavy Ion Collider(RHIC)at Brookhaven National Laboratory(BNL).It provides a unique opportunity to probe the correlation between the po-larized quark and antiquark in the strongly coupled quark-gluon plasma(sQGP)produced in relativistic heavy ion collisions,opening a new window to explore the properties of sQGP.In addition,spin alignments of vector mesons have also been observed in other high-energy particle collisions such as e^(+)e^(−)annihilations at high energies where hadron production is dominated by quark fragmentation mechanism.The results obtained are quite different from those obtained in heavy ion collisions where quark coalescence/combination mechanism dominates suggesting strong dependence on hadronization mechanisms.So comprehensive studies in different hadronization processes are needed.In this article,we present a brief review of theoretical and experimen-tal advances in the study of vector meson’s spin alignments in a variety of high-energy particle collisions,with emphasis on hadronization mechanisms.展开更多
The exclusive photoproduction of vector mesons(J/ψ/andφ)is investigated by considering the next-toleading order corrections in the framework of the color glass condensate.We compare the next-to-leading order modifie...The exclusive photoproduction of vector mesons(J/ψ/andφ)is investigated by considering the next-toleading order corrections in the framework of the color glass condensate.We compare the next-to-leading order modified dipole amplitude with the HERA data,finding a good agreement.Our studies show that theχ~2/d.o.f from the leading order,running coupling,and collinearly improved next-to-leading order dipole amplitudes are 2.159,1.097,and 0.932 for the elastic cross-section,and 2.056,1.449,and 1.357 for the differential cross-section,respectively.The results indicate that the higher-order corrections contribute significantly to the vector meson productions,and the description of the experimental data is dramatically improved once the higher order corrections are included.We extend the next-to-leading order exclusive vector meson production model to LHC energies using the same parameters obtained from HERA.We find that our model provides a rather good description of the J/ψandΦdata in proton-proton collisions at 7 TeV and 13 TeV in LHCb experiments.展开更多
We study the vector meson electro-production off the proton in a QCD inspired model. A calculation of the differential cross section is performed for the J/ψ, Ф meson off the proton. The theoretical results are cons...We study the vector meson electro-production off the proton in a QCD inspired model. A calculation of the differential cross section is performed for the J/ψ, Ф meson off the proton. The theoretical results are consistent with the experimental data, and remind us to consider the contribution from the tensor glueball and Odderon to the differential cross section. Since gluons interact among themselves via self-interaction, the gluons can form a glueball with quantum numbers I^G, J^PC = 0^＋, 2^＋＋ with a decay width Гt = 100 MeV and mass of mG = 2.23 GeV. The three gluons can form a three gluon color bound state with charge conjugation quantum number C = -1. This study is quite important to verify the validity of QCD and to search for new particles （tensor glueball and Odderon） as well as quest for new physics.展开更多
Spin alignments of vector mesons and hyperons in relativistic heavy-ion collisions have been proposed as signals of global polarization.The STAR experiment first observed the ∧ polarization.Recently,the ALICE collabo...Spin alignments of vector mesons and hyperons in relativistic heavy-ion collisions have been proposed as signals of global polarization.The STAR experiment first observed the ∧ polarization.Recently,the ALICE collaboration measured the transverse momentum {PT) and the collision centrality dependence of K*,and Φ spin alignments during Pb-Pb collisions at 1/2sNN=2.76 TeV.A large signal is observed in the low pT region of mid-central collisions for K*,while the signal is much smaller for Φ,and these have not been understood yet.Since vector mesons have different lifetimes and their decay products have different scattering cross sections,they suffer from different hadronic effects.In this paper,we study the effect of hadronic interactions on the spin alignment of K*,Φ,and p mesons in relativistic heavy-ion collisions with a multi-phase transport model.We find that hadronic scatterings lead to a deviation of the observed spin alignment matrix element p00 away from the true value for p and K*mesons(with a bigger effect on p) while the effect is negligible for the Φ meson.The effect depends on the kinematic acceptance:the observed p00 value is lower than the true value when the pseudorapidity(η) coverage is small,while there is little effect when the η coverage is large.Hence,this study provides valuable information to understand the vector meson spin alignment signals observed during the experiments.展开更多
Using an improved lattice Hamiltonian with massive Wilson quarks a variational method is applied to study the dependence of the vector meson mass Mv on the quark mass m and the Wilson parameter r in two-dimensional SU...Using an improved lattice Hamiltonian with massive Wilson quarks a variational method is applied to study the dependence of the vector meson mass Mv on the quark mass m and the Wilson parameter r in two-dimensional SU（Nc） lattice gauge theory. The numerical results show that for Nc = 2, 3, 4, 5, 6, 7, ..., in the scaling window 1 ≤ 1/g^2 ≤ 2, Mv/g is approximately linear in m, but Mv/g obviously does not depend on r （this differs from the quark condensate）. Particularly for m → 0 our numerical results agree very well with Bhattacharya＇s analytical strong coupling result in the continuum, and the value of （δMv/δm） ｜m=0 in two-dimensional SU（Nc） lattice gauge theory is very close to that in Schwinger model.展开更多
Pure leptonic decays of D~*0)(B_^(*s),B_d~*)→l^+l^- and D^(±*)(D_s~*,B^(*+),B_c~*)→lν_l are investigated.The hadronic contributions such as D^0→D^(*0)γ→μ^+μ^- are also explored.We then obtain the updated ...Pure leptonic decays of D~*0)(B_^(*s),B_d~*)→l^+l^- and D^(±*)(D_s~*,B^(*+),B_c~*)→lν_l are investigated.The hadronic contributions such as D^0→D^(*0)γ→μ^+μ^- are also explored.We then obtain the updated branching fractions of the pseudoscalar mesons to lepton pairs are modified by a factor of few percentages.Specifically,the Br(B+→e^+ν_e)is reduced by a factor 13%.展开更多
Based on the generalized QCD vector meson dominance model, we study the electroproduction of a vector meson off a proton in the QCD inspired eikonalized model. Numerical calculations for the total cross section σ tot...Based on the generalized QCD vector meson dominance model, we study the electroproduction of a vector meson off a proton in the QCD inspired eikonalized model. Numerical calculations for the total cross section σ tot and differential cross section dσ/dt are performed for ρ, ω and φ meson electroproduction in this paper. Since gluons interact among themselves （self-interaction）, two gluons can form a glueball with quantum numbers I G , J P C = 0 ＋ , 2 ＋＋ , decay width Γ t ≈ 100 MeV, and mass of m G =2.23 GeV. The three gluons can form a three-gluon colorless bound state with charge conjugation quantum number C = 1, called the Odderon. The mediators of interactions between projectiles （the quark and antiquark pair fluctuated from the virtual photon） and the proton target （a three-quark system） are the tensor glueball and the Odderon. Our calculated results in the tensor glueball and Odderon exchange model fit to the existing data successfully, which evidently shows that our present QCD mechanism is a good description of meson electroproduction off a proton. It should be emphasized that our mechanism is different from the theoretical framework of Block et al. We also believe that the present study and its success are important for the investigation of other vector meson electro- and photoproduction at high energies, as well as for searching for new particles such as tensor glueballs and Odderons, which have been predicted by QCD and the color glass condensate model （CGC）. Therefore, in return, it can test the validity of QCD and the CGC model.展开更多
The roles of the lightest vector mesons ρ and ω in the multi-Skyrmion states are studied using the hidden local symmetry approach up to the next-to-leading order,including the homogeneous Wess-Zumino terms.The low-e...The roles of the lightest vector mesons ρ and ω in the multi-Skyrmion states are studied using the hidden local symmetry approach up to the next-to-leading order,including the homogeneous Wess-Zumino terms.The low-energy constants in the effective field theory are determined using the Sakai-Sugimoto model and the flat-space five-dimensional Yang-Mills action.With only two inputs,m_(ρ) and f_(π),it is possible to determine all low-energy constants without ambiguity.The vector meson effects can be investigated by sequentially integrating vector mesons,and their geometry can be elucidated by comparing the results using the low-energy constants estimated from the Sakai-Sugimoto model and the flat-space five-dimensional Yang-Mills action.We found that theρmeson reduces the masses of the multi-Skyrmion states and increases the overlaps of their constituents,whereas theωmeson repulses the constituents of the multi-Skyrmion states and increases their masses.Therefore,these vector mesons are crucial in the Skyrme model approach to nuclei.We also found that the warping factor,an essential element in the holographic model of QCD,affects the properties of the multi-Skyrmion states and cannot be ignored.展开更多
Vorticities in heavy-ion collisions(HICs)are supposed to induce spin alignment and polarization phenomena of quarks and mesons.In this work,we analyze the spin alignment of vector mesonsϕandρinduced by rotation from ...Vorticities in heavy-ion collisions(HICs)are supposed to induce spin alignment and polarization phenomena of quarks and mesons.In this work,we analyze the spin alignment of vector mesonsϕandρinduced by rotation from quark dynamics in the framework of the Nambu-Jona-Lasinio(NJL)model.The rotating angular velocity induces mass splitting of spin components for vectorϕ,ρmesons M_(ϕ,ρ)(Ω)≃M_(ϕ,ρ)(Ω=0)−szΩ.This behavior contributes to the spin alignment of vector mesonsϕ,ρin an equilibrium medium and naturally explains the negative deviation ofρ00−1/3 for vector mesons.Incidentally,the positive deviation ofρ00−1/3 under the magnetic field can also be easily understood from quark dynamics.展开更多
Exclusive vector meson production is an excellent probe for describing the structure of protons.In this study,based on the dipole model,the differential cross sections,total cross sections,and ratios of the longitudin...Exclusive vector meson production is an excellent probe for describing the structure of protons.In this study,based on the dipole model,the differential cross sections,total cross sections,and ratios of the longitudinal to transverse cross section of the J/ψandρ^(0)productions are calculated with the analytical solution of the Balitsky-Kovchegov(BK)equation.In addition,we consider the influences of two meson wave function models on the results.Our predictions,which are slightly sensitive to meson wave functions,agree with the experimental data.The analytical solution of the BK equation is reliable for description of exclusive vector meson productions in a certain range of Q^(2).展开更多
Motivated by the experimental measurements of D0 radiative decay modes, we have proposed a model to study the D0→ K＊0γ decay, by establishing a link with D0→ K＊0V （V=ρ0, ω） decays through the vector meson dom...Motivated by the experimental measurements of D0 radiative decay modes, we have proposed a model to study the D0→ K＊0γ decay, by establishing a link with D0→ K＊0V （V=ρ0, ω） decays through the vector meson dominance hypothesis. In order to do this properly, we have used the Lagrangians from the local hidden gauge symmetry approach to account for Vγ conversion. As a result, we have found the branching ratio B[D0→ K＊0γ]=（1.55-3.44）×10-4, which is in fair agreement with the experimental values reported by the Belle and BaBar collaborations.展开更多
基金supported by the National Key R&D Program of China(Grant No.2024YFA1611004)the National Natural Science Foundation of China(Grant Nos.12175117,12475084,and 12321005)the Shandong Province Natural Science Foundation(Grant Nos.ZFJH202303 and ZR2024MA012)。
文摘The transverse single-spin asymmetry forρ^(0) production in semi-inclusive deep inelastic scattering was recently reported by the COMPASS Collaboration.Using the Sivers function extracted from pion and kaon productions,we perform a calculation of the Sivers asymmetry within the transverse momentum-dependent factorization.Our results are consistent with the COMPASS data,supporting the universality of the Sivers function in the semi-inclusive deep inelastic scattering process for different final-state hadrons within current experimental uncertainties.While different parametrizations of the Sivers function from global analyses allow describing the data equally well,we obtain very different predictions on the Sivers asymmetry ofρand K^(*)productions at electron-ion colliders,which therefore are expected to provide further constraints.
基金Supported by National Natural Science Foundation of China under Grant Nos.10647002 and 10565001
文摘Based on the quark-gluon contents of nucleon and strongly believing that the force mediators,Pomeronand its counterpart in the conventional approach of Regge theory,for high energy diffractive process would be the tensorglueball and Odderon respectively,we discuss photo-production of vector meson φ off the deuteron at energy less than 3GeV in the QCD inspired model in which the quark gluon degrees of freedom and glueball,Odderon exchange are takeninto account.A calculation is performed for γ + D →φ + D,and the theoretical predictions of the differential crosssection dσ^(γD)) /dt,are presented and compared with available experimental data.Our QCD inspired model reproducesdata quite well in the whole range of the experimental measurements up to |t| ■0.4 GeV.Our results can be used toextract γn→φn data,which cannot be measured in experiment.
文摘Based on Pomeron exchange model, elastic production of vector meson in electro-proton interaction is investigated with both linear and non-linear Pomeron trajectory. A numerical calculation for J/psi production is performed. The effect of the energy scale so and photon virtuality Q(2) on differential cross section are also predicted. A good agreement with experimental data is obtained. Our conclusions are that the Pomeron exchange model is a successful description of J/psi electro-production, the dependence of the differential cross sections on Q2 is negligible, the linear trajectory is a good approximation to non-linearity of the Pomeron trajectory, and the value of the energy scale parameter so is dependent on the momentum transfer, namely its effect is moderate at low momentum transfer but it causes no difference at high momentum transfer vertical bar t vertical bar >= 1.25 GeV2.
基金Supported by the National Science Foundation of China(NSFC)under Grant Nos.11335001,11105153,11405178supported in part by the DFG and the NSFC(No.11261130311)through funds provided to the Sino-Germen CRC 110"Symmetries and the Emergence of Structure in QCD"performed on Tian He-1A supercomputer of the National Supercomputer Center in Tianjin
文摘Vector meson mass values are studied at finite chemical potential and temperature in lattice QCD with lattice size of 24 × 122× 6 using two flavors of staggered quarks. The investigation focuses on the change of the vector meson mass in the critical region close to T c with two different types of chemical potentials switched on: the isoscalar chemical potential μS and its isovector counterpart μV. It is found that the vector meson mass increases in the QGP phase with both chemical potentials and decreases with μS in the confinement phase.
基金Supported by National Natural Science Foundation of China under Grant No. 11075053the Fundamental Research Funds for the Central Universities
文摘In this article,we study the vector meson transitions among the charmonium and bottomonium states with the heavy quark effective theory in a systematic way,and make predictions for the ratios among the vector meson decay widths of a special multiplet to another multiplet.The predictions can be confronted with the experimental data in the future.
基金supported in part by the Major State Basic Research Development Program in China(No.2014CB845401)the National Natural Science Foundation of China(Nos.11421505,11520101004,11275250 and 11322547)
文摘Low-mass vector meson(ρ, ω, and Ф) production at forward rapidity in p+p and d+Au collisions at (~SNN)^(1/2)=200 Ge V is studied within the framework of a multiphase transport model(AMPT). Detailed investigations, including the transverse momentum and the rapidity dependence of low-mass vector meson production in the AMPT model, show that the hadron interaction process is important for a quantitative description of the ρ and ω data.But for the Ф meson, the strange quark production in the AMPT model with the string melting scenario describes the data reasonably well, while the default AMPT model under-predicts the data. The N(Ф)=N(ρ+ω) ratio from the AMPT model with the string melting scenario perfectly describes the data in p+p collisions. For the d+Au collisions, an increased trend of this ratio vs. transverse momentum and the number of participants are observed from the AMPT model. Our results indicate that a precise measurement of the N(Ф)=N(ρ+ω) ratio in d+Au and Au+Au collisions will shed more light on the strangeness production and its dynamics in quark–gluon plasma.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11465021 and 11065010
文摘We calculate inclusive light vector mesons(ρ,ω,and φ) production in relativistic heavy ion collisions based on the idea of gluon saturation in the color glass condensate(CGC) framework.At high energies,the value of saturation momentum becomes larger than the Quantum Chromodynamics(QCD) confinement scale ∧_(QCD),which implies thatα_s(Q_s) <<1.Using the relativistic kinetic theory,we derive the production rate for the light vector mesons produced by gluon-gluon fusion in the k_T-factorization approach.The numerical results indicate that the light vector mesons from the color glass condensate become prominent in p-p,p-Pb,and Pb-Pb collisions at Large Hadron Collider(LHC) energies.
文摘Radiative decay of heavy ground state vector meson V → Pγis treated semi-classically in the scalar strong interaction hadron theory. The treatment successfully employs the new wave function of the vector meson updated here. The ratio of the available J/ψ and decay rates agrees with prediction. The values of the predicted rates are also in order of magnitude agreement with measurements. These agreements are the only ones directly computed from a first principles’ theory.
基金Supported by the National Natural Science Foundation of China(11805064,11975118)State Key Laboratory of Nuclear Physics and Technology,Peking university(NPT2025KFY03)。
文摘In this paper,a formalism is presented for the helicity amplitude analysis of the decays Ψ(2S)→γ_(1)χ_(c)J,χ_(c)J→γ_(2)V(V=p^(0),φ,ω)(subscripts 1 and 2 are used to distinguish the two radiative photons),and the polarization expressions of the P-wave charmonia χ_(c)J and the vector mesons p^(0),φ,ω for experimental measurements at an electron-positron collider.In addition,we derive formulae for the angular distributions of χ_(c1,2)→γV to extract the degree of transverse polarization P_(T) of e^(+)e^(-)pairs with symmetric beam energy as well as the ratios of two helicity amplitudes x(in χ_(c1) decays)and x,y(in χ_(c2) decays),which represent the relative magnitudes of transverse to longitudinal polarization amplitude.The results are validated by Monte Carlo simulation.Finally,the statistical sensitivity of P_(T),x,and y are estimated based on the large Ψ(2S)data samples collected at current and proposed future e^(+)e^(-)colliderexperiments.
基金supported in part by the National Key Research and Development Program of China(Grant No.2022YFA1604900)the National Natural Science Foundation of China(Grant Nos.12025501,11890710,11890713,11890714,12147101,and 12135011)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(Grant No.XDB34030102)the Natural Science Foundation of Shandong Province。
文摘The global spin alignment of vector mesons has been observed by the STAR collaboration at the Relativistic Heavy Ion Collider(RHIC)at Brookhaven National Laboratory(BNL).It provides a unique opportunity to probe the correlation between the po-larized quark and antiquark in the strongly coupled quark-gluon plasma(sQGP)produced in relativistic heavy ion collisions,opening a new window to explore the properties of sQGP.In addition,spin alignments of vector mesons have also been observed in other high-energy particle collisions such as e^(+)e^(−)annihilations at high energies where hadron production is dominated by quark fragmentation mechanism.The results obtained are quite different from those obtained in heavy ion collisions where quark coalescence/combination mechanism dominates suggesting strong dependence on hadronization mechanisms.So comprehensive studies in different hadronization processes are needed.In this article,we present a brief review of theoretical and experimen-tal advances in the study of vector meson’s spin alignments in a variety of high-energy particle collisions,with emphasis on hadronization mechanisms.
基金Supported by the National Natural Science Foundation of China(11765005,11947119,11305040,11847152,11775097)the Fund of Science and Technology Department of Guizhou Province([2018]1023,[2019]5653)+3 种基金the Education Department of Guizhou Province(KY[2017]004)Qian Kehe Platform Talents([2017]5736-027)the National key research and development program of China(2018YFE0104700,CCNU18ZDPY04)the 2018 scientific research startup foundation for the introduced talent of Guizhou University of Finance and Economics(2018YJ60)。
文摘The exclusive photoproduction of vector mesons(J/ψ/andφ)is investigated by considering the next-toleading order corrections in the framework of the color glass condensate.We compare the next-to-leading order modified dipole amplitude with the HERA data,finding a good agreement.Our studies show that theχ~2/d.o.f from the leading order,running coupling,and collinearly improved next-to-leading order dipole amplitudes are 2.159,1.097,and 0.932 for the elastic cross-section,and 2.056,1.449,and 1.357 for the differential cross-section,respectively.The results indicate that the higher-order corrections contribute significantly to the vector meson productions,and the description of the experimental data is dramatically improved once the higher order corrections are included.We extend the next-to-leading order exclusive vector meson production model to LHC energies using the same parameters obtained from HERA.We find that our model provides a rather good description of the J/ψandΦdata in proton-proton collisions at 7 TeV and 13 TeV in LHCb experiments.
基金Supported by National Natural Science Foundation of China (10647002)Guangxi Science Foundation for Young Researchers(0991009)+1 种基金Department of Guangxi Education (200807MS112)Natural Science Foundation of Guangxi University of Technology(0840211)
文摘We study the vector meson electro-production off the proton in a QCD inspired model. A calculation of the differential cross section is performed for the J/ψ, Ф meson off the proton. The theoretical results are consistent with the experimental data, and remind us to consider the contribution from the tensor glueball and Odderon to the differential cross section. Since gluons interact among themselves via self-interaction, the gluons can form a glueball with quantum numbers I^G, J^PC = 0^＋, 2^＋＋ with a decay width Гt = 100 MeV and mass of mG = 2.23 GeV. The three gluons can form a three gluon color bound state with charge conjugation quantum number C = -1. This study is quite important to verify the validity of QCD and to search for new particles （tensor glueball and Odderon） as well as quest for new physics.
基金the Strategic Priority Research Program of Chinese Academy of Sciences(XDB34030000)the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030008)the National Natural Science Foundation of China(12025501,11890710,11890714,11775288)。
文摘Spin alignments of vector mesons and hyperons in relativistic heavy-ion collisions have been proposed as signals of global polarization.The STAR experiment first observed the ∧ polarization.Recently,the ALICE collaboration measured the transverse momentum {PT) and the collision centrality dependence of K*,and Φ spin alignments during Pb-Pb collisions at 1/2sNN=2.76 TeV.A large signal is observed in the low pT region of mid-central collisions for K*,while the signal is much smaller for Φ,and these have not been understood yet.Since vector mesons have different lifetimes and their decay products have different scattering cross sections,they suffer from different hadronic effects.In this paper,we study the effect of hadronic interactions on the spin alignment of K*,Φ,and p mesons in relativistic heavy-ion collisions with a multi-phase transport model.We find that hadronic scatterings lead to a deviation of the observed spin alignment matrix element p00 away from the true value for p and K*mesons(with a bigger effect on p) while the effect is negligible for the Φ meson.The effect depends on the kinematic acceptance:the observed p00 value is lower than the true value when the pseudorapidity(η) coverage is small,while there is little effect when the η coverage is large.Hence,this study provides valuable information to understand the vector meson spin alignment signals observed during the experiments.
基金Supported by Natural Science Foundation of the Education Department of Guangdong Province of China(06Z027)Professor Foundation of Guangdong Education Institute
文摘Using an improved lattice Hamiltonian with massive Wilson quarks a variational method is applied to study the dependence of the vector meson mass Mv on the quark mass m and the Wilson parameter r in two-dimensional SU（Nc） lattice gauge theory. The numerical results show that for Nc = 2, 3, 4, 5, 6, 7, ..., in the scaling window 1 ≤ 1/g^2 ≤ 2, Mv/g is approximately linear in m, but Mv/g obviously does not depend on r （this differs from the quark condensate）. Particularly for m → 0 our numerical results agree very well with Bhattacharya＇s analytical strong coupling result in the continuum, and the value of （δMv/δm） ｜m=0 in two-dimensional SU（Nc） lattice gauge theory is very close to that in Schwinger model.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11375021,11575017the New Century Excellent Talents in University(NCET)under Grant No.NCET-13-0030+1 种基金the Major State Basic Research Development Program of China under Grant No.2015CB856701the Fundamental Research Funds for the Central Universities
文摘Pure leptonic decays of D~*0)(B_^(*s),B_d~*)→l^+l^- and D^(±*)(D_s~*,B^(*+),B_c~*)→lν_l are investigated.The hadronic contributions such as D^0→D^(*0)γ→μ^+μ^- are also explored.We then obtain the updated branching fractions of the pseudoscalar mesons to lepton pairs are modified by a factor of few percentages.Specifically,the Br(B+→e^+ν_e)is reduced by a factor 13%.
基金Supported by Guangxi Science Foundation for Young Researchers(0991009)Department of Guangxi Education(200807MS112)+1 种基金Department of Guangxi Education for the Excellent scholars of Higher Education(2011-54)Doctoral Science Foundation of Guangxi University of Technology(11Z16)
文摘Based on the generalized QCD vector meson dominance model, we study the electroproduction of a vector meson off a proton in the QCD inspired eikonalized model. Numerical calculations for the total cross section σ tot and differential cross section dσ/dt are performed for ρ, ω and φ meson electroproduction in this paper. Since gluons interact among themselves （self-interaction）, two gluons can form a glueball with quantum numbers I G , J P C = 0 ＋ , 2 ＋＋ , decay width Γ t ≈ 100 MeV, and mass of m G =2.23 GeV. The three gluons can form a three-gluon colorless bound state with charge conjugation quantum number C = 1, called the Odderon. The mediators of interactions between projectiles （the quark and antiquark pair fluctuated from the virtual photon） and the proton target （a three-quark system） are the tensor glueball and the Odderon. Our calculated results in the tensor glueball and Odderon exchange model fit to the existing data successfully, which evidently shows that our present QCD mechanism is a good description of meson electroproduction off a proton. It should be emphasized that our mechanism is different from the theoretical framework of Block et al. We also believe that the present study and its success are important for the investigation of other vector meson electro- and photoproduction at high energies, as well as for searching for new particles such as tensor glueballs and Odderons, which have been predicted by QCD and the color glass condensate model （CGC）. Therefore, in return, it can test the validity of QCD and the CGC model.
基金supported by the National Natural Science Foundation of China(Grant Nos.11875147,and 12147103)。
文摘The roles of the lightest vector mesons ρ and ω in the multi-Skyrmion states are studied using the hidden local symmetry approach up to the next-to-leading order,including the homogeneous Wess-Zumino terms.The low-energy constants in the effective field theory are determined using the Sakai-Sugimoto model and the flat-space five-dimensional Yang-Mills action.With only two inputs,m_(ρ) and f_(π),it is possible to determine all low-energy constants without ambiguity.The vector meson effects can be investigated by sequentially integrating vector mesons,and their geometry can be elucidated by comparing the results using the low-energy constants estimated from the Sakai-Sugimoto model and the flat-space five-dimensional Yang-Mills action.We found that theρmeson reduces the masses of the multi-Skyrmion states and increases the overlaps of their constituents,whereas theωmeson repulses the constituents of the multi-Skyrmion states and increases their masses.Therefore,these vector mesons are crucial in the Skyrme model approach to nuclei.We also found that the warping factor,an essential element in the holographic model of QCD,affects the properties of the multi-Skyrmion states and cannot be ignored.
基金the National Natural Science Foundation of China(NSFC)(12235016,12221005)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB34030000)+1 种基金the start-up funding from the University of Chinese Academy of Sciences(UCAS)the Fundamental Research Funds for the Central Universities。
文摘Vorticities in heavy-ion collisions(HICs)are supposed to induce spin alignment and polarization phenomena of quarks and mesons.In this work,we analyze the spin alignment of vector mesonsϕandρinduced by rotation from quark dynamics in the framework of the Nambu-Jona-Lasinio(NJL)model.The rotating angular velocity induces mass splitting of spin components for vectorϕ,ρmesons M_(ϕ,ρ)(Ω)≃M_(ϕ,ρ)(Ω=0)−szΩ.This behavior contributes to the spin alignment of vector mesonsϕ,ρin an equilibrium medium and naturally explains the negative deviation ofρ00−1/3 for vector mesons.Incidentally,the positive deviation ofρ00−1/3 under the magnetic field can also be easily understood from quark dynamics.
基金the Strategic Priority Research Program of Chinese Academy of Sciences(XDB34030301)。
文摘Exclusive vector meson production is an excellent probe for describing the structure of protons.In this study,based on the dipole model,the differential cross sections,total cross sections,and ratios of the longitudinal to transverse cross section of the J/ψandρ^(0)productions are calculated with the analytical solution of the Balitsky-Kovchegov(BK)equation.In addition,we consider the influences of two meson wave function models on the results.Our predictions,which are slightly sensitive to meson wave functions,agree with the experimental data.The analytical solution of the BK equation is reliable for description of exclusive vector meson productions in a certain range of Q^(2).
基金funding agency FAPESP for the financial support(2016/22561-2)the Programa Santiago Grisolia of Generalitat Valenciana(Exp.GRISOLIA/2015/005)+3 种基金partly supported by the Spanish Ministerio de Economiay Competitividad and European FEDER funds(FIS2014-57026-REDT,FIS2014-51948-C2-1-P,FIS2014-51948-C2-2-P)the Generalitat Valenciana in the program Prometeo II-2014/068partly supported by the National Natural Science Foundation of China(11475227,11735003)the Youth Innovation Promotion Association CAS(2016367)
文摘Motivated by the experimental measurements of D0 radiative decay modes, we have proposed a model to study the D0→ K＊0γ decay, by establishing a link with D0→ K＊0V （V=ρ0, ω） decays through the vector meson dominance hypothesis. In order to do this properly, we have used the Lagrangians from the local hidden gauge symmetry approach to account for Vγ conversion. As a result, we have found the branching ratio B[D0→ K＊0γ]=（1.55-3.44）×10-4, which is in fair agreement with the experimental values reported by the Belle and BaBar collaborations.
