非静态球形夸克-胶子等离子体的2π干涉学的检测

提出了一种相对论重离子碰撞中强子物质生成时的π膨胀源模型. 得到了该模型中的小相对论动量区域的2π关联函数及表观π源参数R_a与实际π源参数R_e的关系. 这一关系与QGP生成时的关系有所区别. 这一区别可以用来检测相对论重离子碰撞中产生的非静态球形夸克-胶子等离子体的存在性. 两个关系也显示了一种标度行为.     

Two-Pion Interferometry at Small Relative Momentum Taking Account for Multi-Pion Correlations

A general expression for nπ correlation function is given when there are multi-pion correlations in the choices of correlated nπ and uncorrelated nπ. Using this expression, the two-pion interferometry at small relative momentum which takes account for multi-pion correlations is studied, the relations between the pion source parameters from the two-pion interferometry and the three- pion interferometry are obtained analytically, and comparison is made with the experimental results of central relativistic heavy ion collisions 1.8 A GeV Ar+Pb.     

相对论非对称重离子碰撞中小相对动量区域2π干涉学

用小相对动量区域2π干涉学分析方法研究了相对论非对称重离子碰撞中π介子的吸收存在时对2π干涉学分析所得π源参数的影响,得到了不考虑和考虑π的吸收情况下所得到的源的参数的解析关系.与相对论非对称重离子碰撞1.8A GeVAr+Pb的实验结果进行了对比.     

相对论重离子碰撞中π源密度分布和小相对动量区域2π干涉学分析

用2π关联函数在小相对动量区域的幂级数展开,得到了不同π源密度分布下源的空间参数、平均半径和均方根半径间关系,与相对论重离子中心碰撞1.8A GeV Ar+Pb的实验结果一致. 给出了上述反应中π源的平均半径和均方根半径.对不同的源密度分布,计算了K_t的值.     

柱形夸克胶子等离子体的2π干涉学检测

在2п干涉学中,对不同的п源2п,关联函数可以是不同的. 如果在相对论重离子碰撞中出现柱形夸克胶子等离子体,п介子将从柱形夸克胶子等离子体表面发射,此时2п关联函数将出现一种特殊的振荡行为.这种振荡行为可以用来探明夸克胶子等离子体的存在性,同时也是相对论重离子碰撞中出现夸克胶子等离子体的一个信号.     

Effect of the Choice of the Background on Two-Pion Inter-Ferometry

The effect of the choice of the background on the pion source parameters in two-Pion interferometry analyses in relativistic heavy-ion collisions is studied with the two-Pion interferometry at small relative momentum. The analytic relations between the pion source parameters from two-Pion interferometry analyses with different backgrounds are obtained, and comparison is made with the experimental measurements of the cental relativistic heavy-ion collisions of 1.8 A GeV Ar+Pb.     

An Explanation of a Phenomenon in Relativistic Heavy-Ion Collisions

The multi-source pion interferometry in relativistic heavy-ion collisions is presented and two-source models for hadron gas and hadron gas plus quark-gluon plasma are proposed. The models can resolve the HBT puzzle. For the same $q$ and different direction of \bar{q}, the two-pion correlation functions show characteristic oscillation behaviors, which may be used to distinguish the two-source models. Our research also showes that the multi-source pion correlations can resolve the HBT puzzle.     

Parton coalescence and the antiproton/pion anomaly at RHIC

Coalescence of minijet partons with partons from the quark-gluon plasma formed in relativistic heavy ion collisions is suggested as the mechanism for production of hadrons with intermediate transverse momentum. The resulting enhanced antiproton and pion yields at intermediate transverse momenta give a plausible explanation for the observed large antiproton to pion ratio. With further increasing momentum, the ratio is predicted to decrease and approach the small value given by independent fragmentations of minijet partons after their energy loss in the quark-gluon plasma.     

相对论重离子碰撞中集合流对2π干涉学分析的影响

用小相对动量区域2π干涉学分析方法研究了相对论重离子碰撞中集合流对2π干涉学分析的影响,给出了π源的表观半径与其真实半径的解析关系.     

相对论重离子碰撞中背景的选取对2π干涉学分析的影响

用小相对动量区域2π干涉学分析方法,研究了相对论重离子碰撞中背景的选取对2π干涉学分析所得π源参数的影响,得到了在不同背景下2π干涉学分析所得π源参数之间的解析关系,与相对论重离子中心碰撞1.8A GeV Ar+Pb的实验结果进行了对比.     

Multi-Pion Correlations in Two-Pion Interferometry

The influence of multi-pion correlations on two-pion interferometry analysis in multi-pion events can be expressed as the ratio of a multi pion correlation factor for the sample of like-pion pairs to a residual correlation factor for the reference sample.Although these two correlation factors can be partially cancelled our in data analyses,the difference between these two factors in the low relative momentum region is so large that the distortion on the analysed results of two-pion interferometry from multi-pion interference becomes a serious problem when the pion source has a small radius and the pion multiplicity of event is high.The distributions of multi-pion correlation factor C_n－2(q) can sensitively reflect the multi-pion correlation effects in the events The analyses of multi-pion correlation factor for two Bevalac streamer chamber data samples of 2.1AGeV Ne+Pb and 1.8AGeV Ar+Pb collisions show that the multi-pion correlation effect in the former data sample is greater that in the latter.     

夸克偶素双光子衰变的相对论效应

考虑到各种相对论效应，唯象地研究了0－＋和0＋＋夸克偶素的双光子衰变. 相比于通常用的非相对论近似，我们的相对论唯象方法给出了3种分别由介子内夸克相对动量，相对能量，以及它的自旋形式的选取带来的效应. 在cc和ss中我们做了具体的分析     

Test of Quark-Gluon Plasma of Cylinder Shape by Two-Pion Interferometry

The two-pion correlation functions are different for some pion source distributions in two-pion interferometry.If quark-gluon plasma of cylindrical shape is produced in relativistic heavy ion collisions, the pion mesons will emit from the surface of quark-gluon plasma of cylindrical shape and the corresponding correlation function will have a special oscillation behavior. The oscillation behavior can be used to verify the existence of quark-gluon plasma and is also a signature of the appearance of quark-gluon plasma.     

Two-pion interferometry for viscous hydrodynamic sources

The space-time evolution of the (1+1)-dimensional viscous hydrodynamics with an initial quark-gluon plasma (QGP) produced in ultrarelativistic heavy ion collisions is studied numerically. The particle-emitting sources undergo a crossover transition from the QGP to hadronic gas. We take into account a usual shear viscosity for the strongly coupled QGP as well as the bulk viscosity which increases significantly in the crossover region. The two-pion Hanbury-Brown-Twiss (HBT) interferometry for the viscous hydrodynamic sources is performed. The HBT analyses indicate that the viscosity effect on the two-pion HBT results is small if only the shear viscosity is taken into consideration in the calculations. The bulk viscosity leads to a larger transverse freeze-out configuration of the pion-emitting sources, and thus increases the transverse HBT radii. The results of the longitudinal HBT radius for the source with Bjorken longitudinal scaling are consistent with the experimental data.     

超相对论重离子碰撞中小相对动量区域2π干涉学

用小相对动量区域π干涉学方法给出了超相对论重离子碰撞中两种模型下π源参数的关系,并与200A GeV O+Au碰撞的实验结果进行了对比.     

相对论重离子碰撞中部分相干源的相干因子

给出了两种统计系综下相对论重离子碰撞中部分相干源的相干因子的表达式     

Determining pion source parameters in relativistic heavy-ion collisions

Two-pion inclusive spectra from relativistic heavy-ion collisions are related to single-particle inclusive measurements in a Lorentz-invariant formulation of the Hanbury-Brown-Twiss effect. A thermal pion source with a gaussian space-time distribution is assumed. The angular anisotropy and moments of the correlation function are computed to facilitate the determination of pion source parameters from the ratios of the two-pion to single-pion inclusive data.     

Photon production in relativistic heavy ion collisions with equilibrium and non-equilibrium QGP

We consider the production sources of prompt and thermal photons which include the contribution of gluons in relativistic heavy ion collisions. Considering in our calculation the shadowing and iso-spin effects of the nucleus we can properly estimate the prompt photon production. We develop a new thermal jet-photon conversion mechanism which plays a vital role in the low transverse momentum region. The effect of the non-equilibrium quark-gluon plasma enhances the contribution of thermal photons.     

Photon production in relativistic heavy ion collisions with equilibrium and non-equilibrium QGP

We consider the production sources of prompt and thermal photons which include the contribution of gluons in relativistic heavy ion collisions. Considering in our calculation the shadowing and iso-spin effects of the nucleus we can properly estimate the prompt photon production. We develop a new thermal jet-photon conversion mechanism which plays a vital role in the low transverse momentum region. The effect of the non-equilibrium quark-gluon plasma enhances the contribution of thermal photons.     

Quantum opacity, the RHIC Hanbury Brown-Twiss puzzle, and the chiral phase transition

We present a relativistic quantum-mechanical treatment of opacity and refractive effects that allows reproduction of observables measured in two-pion Hanbury Brown-Twiss (HBT) interferometry and pion spectra at RHIC. The inferred emission duration is substantial. The results are consistent with the emission of pions from a system that has a restored chiral symmetry.