Dissertation > Mathematical sciences and chemical > Physics > Nuclear physics,high energy physics > Nuclear physics > Heavy ion nuclear physics

Two-and Three-Particle Azimuthal Correlations Study in Au+Au Collisions at (?)=200Gev

Author WuJinBo
Tutor YangChunBin
School Central China Normal University
Course Theoretical Physics
Keywords relativistic heavy ion collision quark-gluon plasma Monte Carlo azimuth angle particle correlations
CLC O571.6
Type Master's thesis
Year 2012
Downloads 18
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As we known, Quantum Chromodynamics (QCD) is the most powerful theory to describle the strong interaction at the present, which predicts a new form of matter, which is called quark-gluon plasma (QGP), consisting of freedom quarks,antiquarks and gluons, at extremely high energy densities.Researching the forming and properties of the matter, has become the one of very interesting region. However, how to create the extremely high energy densities at the laboratory? The relativistie heavy ion collision(or called high energy nucleus-nucleus collisions) is the answer. For example, the Relativistie Heavy Ion Collider (RHIC) at the Brookhaven National Laboratory is able to accelerate the energy of the single nuclear to the200GcV, The energy pro-duced is so great in this collisions. To obtain more great energy, the Large Hadron Collider (LHC) has been built at the CERN to make the deeply reseaching this new matter.The data from the RHIC shown that the new form of matter has been pro-duced at the condition of the experiment,however, we just to get the information of the final particles, which has hadronized, at the laboratory. therefore, physicist is how to know the QGP is produced?They found some different signals, which is called the probe of the produced QGP, from the normal matter by way of analyzing the information of the final particles. There are several different physics mechanism have been brought to explain this phenomenon, jet-quenching is one of the powerful mechanisms to probe the produce of the QGP. Two-particle azimuth angle correla-tions is a good way to understanding jet-quenching. The result of the two-particle azimuth angle correlations show that the correlated yield between the trigger-particle whit high transverse momentum (p>2GeV/c) and the associate-particle of it is strongly suppressed, while the yield of is enhanced at the lower transverse momen-tum. We provide a simple model, similar to the Momentum kick model (MKM) and to the Markovian parton scattering model (MPSM), to investigate the two-particle azimuth correlations at the (?)=200GeV Au+Au at the central,semi-central and peripheral collisions according to Monte Carlo simulating the heavy ion collision, our results can fit the experimental data well from PHEXIX and STAR collaboration, respcctivily.A very interesting phenomenon was found at the two-particle azimuthal corre-lations at the (?)=200GeV Au+Au central collisions, i.e. two-humped was found at the away-side of the trigger-particle. A lot of mechanism were present to explain this phenomenon. such as:Broadened-jets. Deflected-jet or energy loss dependent on the path length, Conical emission and Mach-cone. If understanding the underlying mechanism, we maybe know that the medium properties, for example, the speed of sound and equation of state of the medium, so it’s important to distinguish the un-derlying mechanism. We investigate the three-particle azimuth correlations of the away-side of the trigger-particle at the (?)=200GcV at the0-12%central Au+Au collisions applying to our model. Up to now, we just analysis the diagonal and off-diagonal projections of the away-side three-particle azimuthal correlation result and the results can fit well the STAR collaboration. So, we be merely able to say Mach-cone is responsible for conical emission. Our model predict the projections results of away-side of the three-particle azimuthal correlation at the diagonal and off-diagonal from (?)=200GcV Au+Au at the semi-central and peripheral collisions.

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