Photoproduction of Vector Meson φ off Deuteron in QCD Inspired Model

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.

Vector Meson Electro-production in Pomeron Exchange Model

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.

Analysis of Vector Meson Transitions Among Heavy Quarkonium States

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.

Low-mass vector meson production at forward rapidity in p+p and d+Au collisions at (~SNN)^(1/2)=200 GeV from a multiphase transport model

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.

On Radiative Decay of Heavy Vector Mesons <i>V</i>&rarr;<i>P&gamma;</i>in the Scalar Strong Interaction Hadron Theory

Radiative decay of heavy ground state vector meson V → P&gamma;is 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.

Vector meson effects on multi-Skyrmion states from the rational map ansatz

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.

Spin alignment of vector mesons from quark dynamics in a rotating medium

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.

Exclusive photoproduction of vector meson at next-to-leading order from color glass condensate

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.

Vector meson J/ψ,φ electro-production in QCD

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.

The effect of hadronic scatterings on the measurement of vector meson spin alignments in heavy-ion collisions

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.

Vector meson masses in two-dimensional SU(N_C)lattice gauge theory with massive quarks

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.

Vector meson electroproduction in QCD

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.

Vector Meson Mass in Finite Density and Temperature Lattice QCD

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.

Exclusive vector meson production with the analytical solution of Balitsky-Kovchegov equation

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).

The radiative decay D^(0)→ K^(*0)γ with vector meson dominance

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.

Light Vector Mesons Production in Ultrarelativistic Heavy Ion Collisions from the Color Glass Condensate

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.

重离子碰撞中QCD物质整体极化的实验测量

高能重离子碰撞中Λ超子和φ, K*0矢量介子的整体极化的实验数据证实了夸克物质整体极化的新现象,引起了研究人员的广泛关注,成为高能核物理前沿新的热点研究方向.本文主要从实验测量上回顾整体极化研究,着重阐述相对论重离子对撞机(RHIC)上的螺旋径迹探测器(STAR)合作组在不同对撞能量点开展的Λ超子和φ, K*0介子的整体极化测量结果,并拓展到含有多个奇异夸克粒子Ξ,Ω的整体极化测量和Λ沿着束流方向的局域极化研究.本文也将简单点评大型强子对撞机(LHC)能区和HADES实验低能区的测量结果,并对这些实验结果给出的物理信息进行简单描述.

重离子碰撞中的矢量介子自旋排列

在非对心相对论重离子碰撞中,参与反应的系统具有巨大的轨道角动量,从而使产生的夸克胶子等离子体具有极强涡旋场,并通过自旋-轨道相互作用导致部分子的自旋极化,经过强子化导致重子的自旋极化以及矢量介子的自旋排列等可观测效应.矢量介子的自旋排列是指其自旋密度矩阵的00元素ρ00偏离1/3.在矢量介子衰变到两个赝标介子的过程中,衰变产物的极角分布只与ρ00有关,以此可以对自旋排列进行测量.理论研究表明,重离子碰撞过程中,重子的自旋极化反映了夸克自旋极化的时空平均效应,而矢量介子自旋排列则反映了夸克反夸克自旋极化的局域相空间关联.本文回顾了相对论重离子碰撞中矢量介子自旋排列的相关理论工作.重点以非相对论夸克融合模型为例,明确地计入夸克极化的相空间依赖性,展示了矢量介子自旋排列与夸克反夸克自旋极化特别是它们之间相空间关联的关系.本文还讨论了涡旋、电磁场、有效ø介子场以及它们的局域涨落对ø介子自旋排列的贡献,结果显示强作用场的时空关联效应是导致ø介子自旋排列的主要因素.矢量介子自旋排列为探索强相互作用物质和强相互作用场的性质提供了新途径.

高能重离子超边缘碰撞中极化光致反应

本文旨在对近期高能重离子超边缘碰撞中光致产生过程的研究做一个简要综述.相对论性重离子激发的超强电磁场可以被近似认为是一束极高亮度的等效相干光子束流.本文主要讨论两类等效光子参与的高能产生过程:准实光子融合产生轻子对即Breit-Wheeler过程,以及等效光子与原子核内的胶子物质相互作用导致的矢量介子衍射产生过程.这两类过程是研究重离子超边缘碰撞的传统课题,本文主要侧重于讨论碰撞参数依赖效应与末态软光子重求和效应.另一方面,最近一系列研究揭示了相对论重离子所激发的准实光子是高度线性极化的,其极化方向平行于光子横动量方向;并指出可以通过重离子超边缘碰撞中轻子对产生过程的cos4ø方位角不对称来测量光子的线偏振度.这一理论预言随后被SATR合作组的测量所证实.伴随这一新的理论与实验进展,线性极化光子束流同时也给我们提供了一种新颖的实验手段,用来研究量子色动力学唯象学.如线偏振准实光子可导致矢量介子衍射产生过程的各种方位角不对称,通过研究这些方位角不对称可以让我们更深入地理解高能散射过程的双缝干涉效应、库仑-核反应的干涉过程,以及抽取光子维格纳函数等.本文将详述这些效应并讨论未来的理论与实验发展.