重离子碰撞中的介子——兰州重离子冷却储存环上可能实验的讨论

讨论了在兰州重离子加速装置冷却储存环上开展介子产生的实验研究的可能性和进行π和η介子产生研究的意义在 ＣＳＲ能量区域内, 核子可以激发为Δ和 Ｎ,因此, 在研究热密核物质的状态方程时, 考虑Δ和Ｎ自由度是重要的． 观察重离子碰撞中产生的介子可以提供热密核物质的状态方程, 从而可以提供核内物质分布以及 Ｎ在核物质中传播的信息． 建议建造一个测量介子的实验装置, 以开展该领域的研究.The possibilities for experimental study of meson production at Cooling Storage Ring (CSR) of Lanzhou are discussed. It is shown that the study of production of the pion and eta mesons at CSR is of significance. Nucleon can be excited to Δ and N * at CSR energy region. Therefore, it is important to consider the degree of Δ and N * in the study of the equation of states of hot and dense matter. The produced mesons in heavy ion collisions can provide information on...     

Heavy Meson Decay in Three-Mesons and FSI

The final state interaction contribution to charged D decay into \({K \pi \pi}\) is computed within a light-front framework, considering S-wave \({K\pi}\) interactions in 1/2 and 3/2 isospin states. The convergence of the rescattering series is checked computing terms up to the third perturbative order. The role of the resonances above \({K^*_0(1430)}\) , and the contribution of the \({K\pi 3/2}\) isospin channel to charged three-body D decays, are studied against the available phase-shift analysis.     

Heavy Meson Decay Constants to 1/mQ

We introduce the vector meson contributions in heavy-light chiral perturbation theory (HLCPT) and construct the Lagrangian and current. to the order 1/m_Q. With this, to the order 1/∧_csb²(∧_csb is the chiral symmetry breaking scale) we calculate corrections to f_D and f_B arising from coupled-channel effects to the orders 1/m_C, and 1/m_b. At the tree level in HLCPT, using the relativistic Bethe-Salpeter (BS) equation with the kernel containing a confinement term and a gluon exchange term in a covarian t generalization of the coulomb gauge we calculate f_D⁽⁰⁾ and f_B⁽⁰⁾ when m_Q→∞ as well as the 1/m_Q corrections. HLCPT and the heavy quark effective theory (HQET) are matched at the scale ACsb. Adding the perturbative and nonperturbative contributions we give the values for f_D and f_B, respectively. It is found that our result is in agreement with the relation f_D = f_B fiom lattice calculations.     

重离子碰撞中的轻矢量介子光生过程(英文)

计算了相对论重离子碰撞中轻矢量介子(ρ,ω和φ)的光生过程。基于窄-宽近似,严格推导了相对论重离子碰撞中ρ,ω和φ半弹性和非弹性光生过程的遍举和单举横截面。从数值结果可以看出对于p-p碰撞,光生过程的贡献是不重要的,但是对于pT2.5 GeV Au-Au碰撞和pT3 GeV Pb-Pb碰撞,轻矢量介子光生过程的贡献是明显的。     

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.     

Exotic Baryons from a Heavy Meson and a Nucleon

We study hadronic molecules formed by a heavy meson and a nucleon respecting heavy quark symmetry. It is shown that the tensor force plays a dominant role to yield a strong attraction in this system.     

Heavy Mesons Spectroscopy

In this paper, Lippmann-Schwinger equation is solved by using Martin and Cornel potentials to calculate $b\bar{c}$ energy levels. The results for some energy levels which are not observable, such as those of $t\bar{t}$ in its short half-life are also predicted. Our calculated energy levels are in good agreement with results of other groups. The stability interval for Yukawa-Linear potential is also studied by investigating the spectrum of eigenvalues.     

Photoproduction of Light Vector Meson in Relativistic Heavy Ion Collisions

We calculate the hard photoproduction of light vector meson from the fragmentation of photon in Pb Pb col- lisions. Using the perturbative quantum chromodynamics calculation, we rigorously derive the electromagnetic fragmentation production for p, co and Ф in relativistic nucleus-nucleus collisions by the photoproduction pro- cesses. It is shown that the differential cross section of photoproduction processes of light vector meson cannot be negligible in relativistic heavy ion collisions at Large Hadron Collider energies.     

Mechanisms of B Meson Suppression in Ultrarelativistic Heavy Ion Collisions

Journal of Experimental and Theoretical Physics - Different mechanisms of B meson suppression in lead ion collisions at an energy of the Large Hadron Collider $$sqrt {{{s}_{{NN}}}} $$ = 5.02 TeV...     

CSR能区重离子反应中的介子产生

重离子反应中介子产生的观测对于认识重离子反应动力学和核物质性质具有重要的意义 .讨论了重离子反应中阈能附近介子产生的一些特点和研究现状 ,特别讨论了π介子产生和K+ 介子产生 .在我国兰州重离子冷却储存环上开展这方面的实验研究具有可能性 ,可望得到很有意义的结果 .及时开展这方面实验研究和相应的理论研究是必要的.It is important to measure meson productions in heavy ion collisions in order to understand the dynamics of heavy ion reactions and the properties of nuclear matter. In this paper we review the characteristic and present status of meson productions near the threshold energies in heavy ion collisions. Especially the pion and K + productions are discussed. We point out that it is meaningful and possible to carry out the experimental studies at the CSR. It is necessary to carry out timely the...     

Meson spectrum

Using the Klein-Gordon equation with a box potential, a mass formula describing the family of nonflavored meson states withI=1 is derived. The energy levels calculated agree with those observed within an accuracy of 5%. In the model discussed quarks behave like tachyons.     

Bc Meson Studies

Our studies on the meson Bc are briefly reviewed. The decays of the meson Bc to a P-wave charmonium χc or hc are reported comparatively precisely because they are fresh results obtained recently.     

On Meson Masses

It is shown that in the framework of an analytical confinement, when quark and gluon propagators are induced by a vacuum self-dual gluon field with constant strength, the masses of mesons with quantum numbers Q = (J ^P ,n), where n is the radial quantum number, and quark constituents m ₁, m ₂ are described with reasonable accuracy by the formula The positive parameter A _Q is unique for all mesons with a fixed quantum number Q. Sets of mesons J ^P = 1⁻, 0⁺, 1⁺, 2⁺, 3⁻ for n = 0 and 1⁻ , 2⁺ for n > 0 and different flavor constituent quarks (u = d, s, c, b) are considered.     

A Study of One S- and One P-Wave Heavy Meson Interaction in a Chiral Quark Model

The analytical forms of the interaction potentials between one pseudo-scalar/vector and one scalar/tensor/axial-vector heavy mesons are deduced based on a chiral quark model. Our results explicitly show the attractive property between the two heavy mesons. Consequently, a series of possible molecular states are obtained. It is expected that our study might shed some light on the popular discussions of the newly observed XYZ states.     

Some New Features in the Pseudoscalar Meson and Vector Meson Photoproductions

We investigate the role of the t-channel meson exchange in various photoproduction processes to discuss features of the respective production mechanism. For the less model-dependent analysis we work with the t-channel meson pole reggeized in the Born approximation amplitude. With the meson–baryon coupling constants chosen consistently with symmetry prediction we show that the Reggeized pole model could reproduce the experimental data to a good degree in the lower energy region. Numerical consequences show the significance of the tensor meson exchange in the γ p → K ⁺Λ, the dominance of the pseudoscalar meson exchange in the πΔ (and KΣ*) processes, and the sizable role of the vector-meson magnetic moment in the charged ρ (and K*) photoproductions, respectively. These new features from the present analyses could provide a useful guide for future study of the N* resonances in the low energy region.     

Meson decays of hypertritium

Using ³ H and³He wave functions found by multiparameter variation calculations with N-potentials consistent with fundamental hypernuclear data and Afnan-Tang and Malfiet-Tjon type NN-potentials, the fraction of two particle ^–-decays in the total number of ^–-decays in ³ H is calculated and the ³ H lifetime is estimated. The results obtained are compared with experimental data on decay and binding energy of ³ H.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 44–48, March, 1988.