Download or read book Azimuthal Asymmetry of Particle Production in Au Au Collisions at 11 6 A GeV written by and published by . This book was released on 1996 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Particle production was measured by the E866 forward spectrometer. It was reported earlier in our publication that a correlation between particle ratios and the asymmetry of energy deposition in zero degree calorimeter(ZCAL) was found. To further investigate the azimuthal asymmetry analysis, the forward hodoscope (HODO) was incorporated and the correlation between the particle production and the ''reaction plane'' will be discussed. Preliminary analysis shows enhanced in- plain proton production.
Download or read book AGS Experiments written by and published by . This book was released on 1999 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book C AD Experiments 2000 2004 written by P. Lo Presti and published by . This book was released on 2004 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Charge Multiplicity Asymmetry Correlation Study Searching for Local Parity Violation at RHIC for STAR Collaboration written by Quan Wang and published by Springer Science & Business Media. This book was released on 2013-08-13 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: It has been suggested that local parity violation (LPV) in Quantum Chromodynamics (QCD) would lead to charge separation of quarks by the Chiral Magnetic Effect (CME) in heavy ion collisions. Charge Multiplicity Asymmetry Correlation Study Searching for Local Parity Violation at RHIC for STAR Collaboration presents the detailed study of charge separation with respect to the event plane. Results on charge multiplicity asymmetry in Au+Au and d+Au collisions at 200 GeV by the STAR experiment are reported. It was found that the correlation results could not be explained by CME alone. Additionally, the charge separation signal as a function of the measured azimuthal angle range as well as the event-by-event anisotropy parameter are studied. These results indicate that the charge separation effect appears to be in-plane rather than out-of-plane. It is discovered that the charge separation effect is proportional to the event-by-event azimuthal anisotropy and consistent with zero in events with zero azimuthal anisotropy. These studies suggest that the charge separation effect, within the statistical error, may be a net effect of event anisotropy and correlated particle production. A potential upper limit on the CME is also presented through this data.
Download or read book Particle type Dependence of Azimuthal Anisotropy and Nuclearmodification of Particle Production in Au Au Collisions at SNN written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present STAR measurements of the azimuthal anisotropy parameter v2 and the binary-collision scaled centrality ratio R{sub CP} for kaons and lambdas ([Lambda] + {bar [Lambda]}) at mid-rapidity in Au+Au collisions at √s{sub NN} = 200 GeV. In combination, the v2 and R{sub CP} particle-type dependencies contradict expectations from partonic energy loss followed by standard fragmentation in vacuum. We establish p{sub T} ≈ 5 GeV/c as the value where the centrality dependent baryon enhancement ends. The K{sub S}° and {Lambda} + {bar {Lambda}} v2 values are consistent with expectations of constituent-quark-number scaling from models of hadron formation by parton coalescence or recombination.
Download or read book Identified Particle Production Azimuthal Anisotropy and Interferometry Measurements in Au Au Collisions at Sqrt SNN written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the first measurements of identified hadron production, azimuthal anisotropy, and pion interferometry from Au+Au collisions below the nominal injection energy at the Relativistic Heavy-Ion Collider (RHIC) facility. The data were collected using the large acceptance STAR detector at (square root)s{sub NN} = 9.2 GeV from a test run of the collider in the year 2008. Midrapidity results on multiplicity density (dN/dy) in rapidity (y), average transverse momentum (p{sub T}), particle ratios, elliptic flow, and HBT radii are consistent with the corresponding results at similar (square root)s{sub NN} from fixed target experiments. Directed flow measurements are presented for both midrapidity and forward rapidity regions. Furthermore the collision centrality dependence of identified particle dN/dy, p{sub T}, and particle ratios are discussed. These results also demonstrate that the capabilities of the STAR detector, although optimized for (square root)s{sub NN} = 200 GeV, are suitable for the proposed QCD critical point search and exploration of the QCD phase diagram at RHIC.
Download or read book Azimuthal Anisotropy in Gold gold Collisions at 4 5 GeV Center of mass Energy Per Nucleon Pair Using Fixed target Mode at the Relativistic Heavy Ion Collider written by Yang Wu and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Perspectives in Hadronic Physics written by Sigfrido Boffi and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the invited and contributed papers presented at the Fourth International Conference on Perspectives in Hadronic Physics and sent to the Editors within the deadline. The Conference was held at the Abdus Salam International Centre for Theoretical Physics (ICTP), Trieste, Italy, from May 12th to 16th, 2003, and was attended by about 100 scientists from 20 countries. The series ofConferences on Perspectives on Hadronic Physics takes place every two years since 1997 and follows the seven Workshops on Perspectives in Nuclear Physics at Intermediate Energies, organized every two years at ICTP since 1983. The aim of these Conferences is to discuss the status-of-the-art concerning the experimental and theoretical investigations of hadronic systems, from nucleons to nuclei and dense nuclear matter, in terms of the relevant underlying degrees of freedom. For such a reason the Fourth Conference has been focused on those experimental and theoretical topics which have been in the last few years the object of intensive investigations, viz. the various approaches employed to describe the structure of hadrons in terms of QCD and QCD inspired models, the recent developments in the treatment of the properties and propagations of hadronic states in the medium, the relevant progress done in the solution of the few- and many- hadron problems, the recent results in the experimental investigation of dense hadronic matter and, last but not least, the physics programs of existing Laboratories and the suggested projects for new Facilities.
Download or read book Phenomenology Of Ultra relativistic Heavy ion Collisions written by Wojciech Florkowski and published by World Scientific Publishing Company. This book was released on 2010-03-24 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gives an introduction to main ideas used in the physics of ultra-relativistic heavy-ion collisions. The links between basic theoretical concepts (discussed gradually from the elementary to more advanced level) and the results of experiments are outlined, so that experimentalists may learn more about the foundations of the models used by them to fit and interpret the data, while theoreticians may learn more about how different theoretical ideas are used in practical applications. The main task of the book is to collect the available information and establish a uniform picture of ultra-relativistic heavy-ion collisions. The properties of hot and dense matter implied by this picture are discussed comprehensively. In particular, the issues concerning the formation of the quark-gluon plasma in present and future heavy-ion experiments are addressed.
Download or read book First Moment of Azimuthal Anisotropy in Au Au Collisions from the Beam Energy Scan at the Relativistic Heavy Ion Collider written by Prashanth Shanmuganathan and published by . This book was released on 2016 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excited nuclear matter at high temperature and density results in the creation of a new state of matter called Quark Gluon Plasma (QGP). It is believed that the Universe was in the QGP state a few millionths of a second after the Big Bang. A QGP can be experimentally created for a very brief time by colliding heavy nuclei, such as gold, at ultra-relativistic energies. The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory consists of two circular rings, 3.8 km in circumference, which can accelerate heavy nuclei in two counter-rotating beams to nearly the speed of light (up to 100 GeV per beam). STAR (Solenoidal Tracker At RHIC) is one of two large detectors at the RHIC facility, and was constructed and is operated by a large international collaboration made up of more than 500 scientists from 56 institutions in 12 countries. STAR has been taking data from heavy ion collisions since the year 2000. An important component of the physics effort of the STAR collaboration is the Beam Energy Scan (BES), designed to study the properties of the Quantum Chromodynamics (QCD) phase diagram in the regions where a first-order phase transition and a critical point may exist. Phase-I of the BES program took data in 2010, 2011 and 2014, using Au+Au collisions at a center-of-mass energy per nucleon pair of 7.7, 11.5, 14.5, 19.6, 27 and 39 GeV. It is by now considered a well-established fact that the QGP phase exists. However, all evidence so far indicates that there is a smooth crossover when normal hadronic matter becomes QGP and vice versa in collisions at the top energy of RHIC (and likewise at the Large Hadron Collider at the CERN laboratory in Switzerland). At these very high energies, the net density of baryons like nucleons is quite low, since there are almost equal abundances of baryons and antibaryons. It is known that net-baryon compression increases as the beam energy is lowered below a few tens of GeV. Of course, if the beam energy is too low, then the QGP phase cannot be produced at all, so it has been proposed that there is an optimum beam energy, so far unknown, where phenomena like a first-order phase transition and a critical point might be observed. On the other hand, there also exists the possibility that a smooth crossover to QGP occurs throughout the applicable region of the QCD phase diagram. Experiments are needed to resolve these questions. In this dissertation, I focus on one of the main goals of the BES program, which is to search for a possible first-order phase transition from hadronic matter to QGP and back again, using measurements of azimuthal anisotropy. The momentum-space azimuthal anisotropy of the final-state particles from collisions can be expressed in Fourier harmonics. The first harmonic coefficient is called directed flow, and reflects the strength of the collective sideward motion, relative to the beam direction, of the particles. Models tell us that directed flow is imparted during the very early stage of a collision and is not much altered during subsequent stages of the collision. Thus directed flow can provide information about the early stages when the QGP phase exists for a short time. A subset of hydrodynamic and nuclear transport model calculations with the assumption of a first-order phase transition show a prominent dip in the directed flow versus beam energy. I present directed flow and its slope with respect to rapidity, for identified particle types, namely lambda, anti-lambda and kaons as a function of beam energy for central, intermediate and peripheral collisions. The production threshold of neutral strange particles requires them to be created earlier, and these particles have relatively long mean free path. Thus these particles may probe the QGP at earlier times. In addition, new Lambda measurements can provide more insight about baryon number transported to the midrapidity region by stopping process of the nuclear collision. It is noteworthy that net-baryon density (equivalent to baryon chemical potential) depends not only on beam energy but also on collision centrality. The centrality dependence of directed flow and its slope are also studied for all BES energies for nine identified particle types, lambda, anti-lambda, neutral kaons, charged kaons, protons, anti-protons, and charged pions. These detailed results for many particle species, where both centrality and beam energy are varied over a wide range, strongly constrain models. The measurements summarized above pave the way for a new round of model refinements and subsequent comparisons with data. If the latter does not lead to a clear conclusion, the BES Phase-II program will take data in 2019 and 2020 with an upgraded STAR detector with wider acceptance, greatly improved statistics, and will extend measurements to new energy points.
Download or read book Characterization of Au Au Collisions at center of Mass Energy written by Brooke Haag and published by . This book was released on 2009 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Particle Production in Au Au Collisions from BNL E866 written by and published by . This book was released on 1996 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this article, we present recent results on particle production from Au+Au collisions at 11 A GeV/c obtained by the E866 experiment. The experiment studies the particle production in high baryon density matter created in central Au + Au collisions. Preliminary results of proton and pion production have been reported in previous Quark Matter conferences. Two particle correlation data for Au + Au collisions in this experiment are presented in another paper in this conference.
Download or read book Gamma Ray And Particle Production In Heavy Ion Reactions Proceedings Of Ii Taps Workshop written by Jose Diaz and published by World Scientific. This book was released on 1994-10-25 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings treat the production of high energy gamma rays and particles (mesons and dileptons) in heavy ion reactions from energies of about 30 MeV·A to a few GeV·A, and its application to the study of the Nuclear Equation of State from both the experimental and theoretical points of view. Giant resonances, intensity interferometry, meson fotoproduction and applications of intermediate energy heavy ion beams are also discussed.
Download or read book Azimuthal Anisotophy in U U and Au Au Collisions at RHIC written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- and four-particle cumulants, v2{2} and v2{4}, for charged hadrons from U+U collisions at √SNN = 193 GeV and Au+Au collisions at √SNN = 200 GeV. Nearly fully overlapping collisions are selected based on the energy deposited by spectators in zero degree calorimeters (ZDCs). Within this sample, the observed dependence of v2{2} on multiplicity demonstrates that ZDC information combined with multiplicity can preferentially select different overlap configurations in U+U collisions. As a result, we also show that v2 vs multiplicity can be better described by models, such as gluon saturation or quark participant models, that eliminate the dependence of the multiplicity on the number of binary nucleon-nucleon collisions.
Download or read book Proceedings of the Conference on Continuous Advances in QCD 2006 written by Marco M. Peloso and published by World Scientific. This book was released on 2007 with total page 611 pages. Available in PDF, EPUB and Kindle. Book excerpt: The volume contains the proceedings of the workshop Continuous Advances in QCD 2006, hosted by the Wiliam I Fine Theoretical Physics Institute. This biennial workshop was the seventh meeting of the series, held at the University of Minnesota since 1994. The workshop gathered together about 110 scientists (a record number for the event), including most of the leading experts in quantum chromodynamics and non-Abelian gauge theories in general.
Download or read book Physics Briefs written by and published by . This book was released on 1993 with total page 1206 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of Non flow Correlations and Elliptic Flow Fluctuations in Au Au Collisions at Relativistic Heavy Ion Collider written by Burak Han Alver and published by . This book was released on 2010 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of collective flow and two-particle correlations have proven to be effective tools for understanding the properties of the system produced in ultrarelativistic nucleus-nucleus collisions at the Relativistic Heavy Ion Collider (RHIC). Accurate modeling of the initial conditions of a heavy ion collision is crucial in the interpretation of these results. The anisotropic shape of the initial geometry of heavy ion collisions with finite impact parameter leads to an anisotropic particle production in the azimuthal direction through collective flow of the produced medium. In "head-on" collisions of Copper nuclei at ultrarelativistic energies, the magnitude of this "elliptic flow" has been observed to be significantly large. This is understood to be due to fluctuations in the initial geometry which leads to a significant anisotropy even for most central Cu+Cu collisions. This thesis presents a phenomenological study of the effect of initial geometry fluctuations on two-particle correlations and an experimental measurement of the magnitude of elliptic flow fluctuations which is predicted to be large if initial geometry fluctuations are present. Two-particle correlation measurements in Au+Au collisions at the top RHIC energies have shown that after correction for contributions from elliptic flow, strong azimuthal correlation signals are present at A0 = 0 and A0 ~ 120. These correlation structures may be understood in terms of event-by-event fluctuations which result in a triangular anisotropy in the initial collision geometry of heavy ion collisions, which in turn leads to a triangular anisotropy in particle production. It is observed that similar correlation structures are observed in A Multi-Phase Transport (AMPT) model and are, indeed, found to be driven by the triangular anisotropy in the initial collision geometry. Therefore "triangular flow" may be the appropriate description of these correlation structures in data. The measurement of elliptic flow fluctuations is complicated by the contributions of statistical fluctuations and other two-particle correlations (non-flow correlations) to the observed fluctuations in azimuthal particle anisotropy. New experimental techniques, which crucially rely on the uniquely large coverage of the PHOBOS detector at RHIC, are developed to quantify and correct for these contributions. Relative elliptic flow fluctuations of approximately 30-40% are observed in 6-45% most central Au+Au collisions at s NN= 200 GeV. These results are consistent with the predicted initial geometry fluctuations.
