共查询到18条相似文献,搜索用时 125 毫秒
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基于一个描述夸克胶子火柱演化的相对论流体力学模型,研究了夸克相、强子相互作用以及非热过程(DrellYan对、粲强子衰变)的中等质量双轻子的产生.发现由于相边对夸克胶子物质演化的影响和RHIC能量核碰撞产生的夸克胶子物质具有高的初始温度,夸克相对双轻子的贡献显著增强,比那些来自强子相互作用的贡献重要,甚至能与来自非热的贡献比较.表明中等质量双轻子的增强是一个在核碰撞中产生了夸克胶子物质的可能信号.
关键词:
夸克-胶子物质
双轻子增强
相对论流体力学模型 相似文献
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运用相对论性的流体力学模型,研究了夸克-胶子火球的双轻子产生,发现随着初始温度的增加零重子的夸克-胶子火球的双轻子总产额在一个平台后单调地上升,而随着初始重子密度的增加富重子的夸克-胶子火球的双轻子总产额呈现一个样.夸克-胶子物质在碰撞中形成的特征可在将来的CERN和Brookhaven实验中得到检验. 相似文献
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双轻子是研究夸克物质的形成和性质的重要探针.本文基于化学平衡化的黏滞性夸克胶子等离子体演化模型,计算了相对论重离子碰撞能量下金-金对心碰撞形成的夸克胶子等离子体中的双轻子产额.在黏滞性计算中加入了胶子非弹性散射过程对黏滞系数的贡献.相较仅考虑夸克和胶子弹性散射的情况,双轻子的产额有较明显的降低.这表明在黏滞系数中加入胶子非弹性散射的贡献使得系统的演化过程加快,演化时间变短. 相似文献
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B. Kämpfer M. I. Gorenstein O. P. Pavlenko 《Zeitschrift fur Physik C Particles and Fields》1990,45(3):491-495
The correlation between dilepton yields and pion multiplicities from the thermalized baryon-poor central region matter produced in ultra-relativistic nucleus-nucleus collisions is analyzed within a hydrodynamical framework. A “cut-in” (or a concave section) in the correlation function is predicted as signal of the deconfinement transition. Transverse flow effects, finite hadronization times of the deconfined matter and realistic initial matter distribution tend to enhance this signal. The need of a refined background subtraction is pointed out to discriminate the dileptons stemming from hard initial interactions and pre-equilibrium processes. 相似文献
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A.V. Leonidov P.V. Ruuskanen 《The European Physical Journal C - Particles and Fields》1998,4(3):519-524
Using a Hagedorn resonance gas picture and quark-hadron duality we estimate the dilepton emission rate in the vicinity of
the QCD deconfinement phase transition. The result is then used to calculate a dilepton spectrum in ultrarelativistic heavy
ion collisions. We show that multibody contributions taken into account in the Hagedorn resonance gas approach provide an
enhancement of the production rate massive dileptons as compared to the previously considered sources.
Received: 20 October 1997 / Published online: 10 March 1998 相似文献
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B. Kämpfer O. P. Pavlenko M. I. Gorenstein A. Peshier G. Soff 《Zeitschrift für Physik A Hadrons and Nuclei》1995,353(1):71-77
The influence of a non-vanishing baryon charge on the rapidity distribution of dileptons produced in ultrarelativistic heavy-ion collisions is studied. We employ a frozen motion model with scaling invariant expansion of the hadronizing quark-gluon plasma as well as a realistic rapidity distribution of secondary particles (i.e., pions and baryons) expected for RHIC energies. We demonstrate a sizeable suppression of the thermal dilepton yield at large rapidities due to the finite baryon density. This affects the most favorable rapidity window for using dileptons for the diagnostic of the quark-gluon plasma and the early temperature distribution of the hot reaction zone. To discriminate the thermal dileptons from Drell-Yan background we propose to utilize the dilepton yield scaled suitably by the pion multiplicity as function of rapidity. 相似文献
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《Nuclear Physics A》1997,614(4):552-564
From the full stopping scenario, the dilepton production in a baryon-rich quark-gluon fireball has been studied based on a relativistic hydrodynamic model. Due to the influence of the phase boundary on the evolution of the system, the quark phase gives the dominant contribution to the dilepton spectrum. In particular, with increasing initial baryon density, the total dilepton yield first rapidly rises when the initial hadronic system goes to the initial quark system, then goes down owing to the suppression of the dilepton production, thus making a characteristic peak signaling the formation of the baryon-rich quark-gluon matter which appears in the total yield. These characteristics can be tested in future experiments at CERN and Brookhaven. 相似文献
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O. V. Teryaev 《Physics of Atomic Nuclei》2012,75(6):748-752
The manifestations of axial anomaly and related effects in heavy-ion collisions are considered. Special role is played by various asymmetries. The azimuthal correlational asymmetries of neutron pairs at NICA/FAIR energy range may probe the global rotation of strongly interacting matter. The conductivity is related to the angular asymmetries of dilepton pairs. The strong magnetic field generated in heavy-ion collisions leads to the excess of soft dileptons flying predominantly in the scattering plane. 相似文献
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We calculate the production of large mass dileptons from the passage of jets passing through the quark-gluon plasma. Using the relativistic kinetic theory, we rigorously derive the production rate for the jet-dilepton conversion in the hot medium. The jet-dilepton conversion is compared with the thermal dilepton emission and the Drell-Yan process. The contribution of the jet-dilepton conversion is not prominent for all values of the invariant mass M, and the Drell-Yan process is found to dominate over the thermal dilepton emission and the jet-dilepton conversion for M>2.5 GeV at RHIC. The jet-dilepton conversion is the dominant source of large mass dileptons in the range of 4 GeV<M<10 GeV at LHC. 相似文献
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In the framework of the thermo field dynamics (TFD) we discuss thermal production of dileptons in quark gluon plasma (QGP) of finite temperature and density up to the first order of QCD correction. We show that the temperature effect to the thermal production rate is rather different from that of the chemical potential, in fact, they give rise to opposite effects which may influence the observation of the dilepton production in QGP. 相似文献