PHENIX has measured the transverse momentum (pT) spectra and two particle angular correlations for high pT particles in d+Au collisions at psNN=200 GeV using the RHIC Year-2008 run data. The azimuthal angle correlations for two particles with a large rapidity gap exhibit a ridge-like structure. Using the pi-0s reconstructed in the EMCal, we have successfully extended the pT reach of the correlation up to 8 GeV/c. We find that the azimuthal anisotropy of hadrons found at low pT persists up to 6 GeV/c with a significant centrality and pT dependence, similar to what was observed in A+A collisions.
The pseudorapidity asymmetry and centrality dependence of charged hadron spectra in d+Au collisions at (square root)s{sub NN} = 200 GeV are presented. The charged particle density at mid-rapidity, its pseudorapidity asymmetry and centrality dependence are reasonably reproduced by a Multi-Phase Transport model, by HIJING, and by the latest calculations in a saturation model. Ratios of transverse momentum spectra between backward and forward pseudorapidity are above unity for p{sub T} below 5 GeV/c. The ratio of central to peripheral spectra in d+Au collisions shows enhancement at 2
The PHENIX experiment at RHIC has measured the centrality dependence of the direct photon yield from Au+Au collisions at √sNN = 200 GeV down to pT = 0.4 GeV/c. Photons are detected via photon conversions to e+e− pairs and an improved technique is applied that minimizes the systematic uncertainties that usually limit direct photon measurements, in particular at low pT . In this paper, we find an excess of direct photons above the Ncoll-scaled yield measured in p+p collisions. This excess yield is well described by an exponential distribution with an inverse slope of about 240 MeV/c in the pT range from 0.6-2.0 GeV/c. Finally, in this study, while the shape of the pT distribution is independent of centrality within the experimental uncertainties, the yield increases rapidly with increasing centrality, scaling approximately with N [alpha] part, where [alpha] = 1.38±0.03(stat)±0.07(syst).
Forward-backward multiplicity correlation strengths have been measured with the STAR detector for Au+Au and p+p collisions at (square root)s{sub NN} = 200 GeV. Strong short and long range correlations (LRC) are seen in central Au+Au collisions. The magnitude of these correlations decrease with decreasing centrality until only short range correlations are observed in peripheral Au+Au collisions. Both the Dual Parton Model (DPM) and the Color Glass Condensate (CGC) predict the existence of the long range correlations. In the DPM the fluctuation in the number of elementary (parton) inelastic collisions produces the LRC. In the CGC longitudinal color flux tubes generate the LRC. The data is in qualitative agreement with the predictions from the DPM and indicates the presence of multiple parton interactions.
This book attempts to cover the fascinating field of physics of relativistic heavy ions, mainly from the experimentalist's point of view. After the introductory chapter on quantum chromodynamics, basic properties of atomic nuclei, sources of relativistic nuclei, and typical detector set-ups are described in three subsequent chapters. Experimental facts on collisions of relativistic heavy ions are systematically presented in 15 consecutive chapters, starting from the simplest features like cross sections, multiplicities, and spectra of secondary particles and going to more involved characteristics like correlations, various relatively rare processes, and newly discovered features: collective flow, high pT suppression and jet quenching. Some entirely new topics are included, such as the difference between neutron and proton radii in nuclei, heavy hypernuclei, and electromagnetic effects on secondary particle spectra.Phenomenological approaches and related simple models are discussed in parallel with the presentation of experimental data. Near the end of the book, recent ideas about the new state of matter created in collisions of ultrarelativistic nuclei are discussed. In the final chapter, some predictions are given for nuclear collisions in the Large Hadron Collider (LHC), now in construction at the site of the European Organization for Nuclear Research (CERN), Geneva. Finally, the appendix gives us basic notions of relativistic kinematics, and lists the main international conferences related to this field. A concise reference book on physics of relativistic heavy ions, it shows the present status of this field.
Annotation. Text reviews the major topics in Quark-Gluon Plasma, including: the QCD phase diagram, the transition temperature, equation of state, heavy quark free energies, and thermal modifications of hadron properties. Includes index, references, and appendix. For researchers and practitioners.
The phase structure of particle physics shows up in matter at extremely high densities and/or temperatures as they were reached in the early universe, shortly after the big bang, or in heavy-ion collisions, as they are performed nowadays in laboratory experiments. In contrast to phase transitions of condensed matter physics, the underlying fundamental theories are better known than their macroscopic manifestations in phase transitions. These theories are quantum chromodynamics for the strong interaction part and the electroweak part of the Standard Model for the electroweak interaction. It is their non-Abelian gauge structure that makes it a big challenge to predict the type of phase conversion between phases of different symmetries and different particle contents. The book is about a variety of analytical and numerical tools that are needed to study the phase structure of particle physics. To these belong convergent and asymptotic expansions in strong and weak couplings, dimensional reduction, renormalization group studies, gap equations, Monte Carlo simulations with and without fermions, finite-size and finite-mass scaling analyses, and the approach of effective actions as supplement to first-principle calculations.
The past decade has seen the development of the operational understanding of fun damental interactions within the standard model. This has detoured our attention from the great enigmas posed by the dynamics and collective behavior of strongly interacting particles. Discovered more than 30 years ago, the thermal nature of the hadronic particle spectra has stimulated considerable theoretical effort, which so far has failed to 'confirm' on the basis of microscopic interactions the origins of this phenomenon. However, a highly successful Statistical Bootstrap Model was developed by Rolf Hagedorn at CERN about 30 years ago, which has led us to consider the 'boiling hadronic matter' as a transient state in the trans formation of hadronic particles into their melted form which we call Quark-GIuon-Plasma (QGP). Today, we return to seek detailed understanding of the thermalization processes of hadronic matter, equipped on the theoretical side with the knowledge of the fundamental strong interaction theory, the quantum chromo-dynamics (QCD), and recognizing the im portant role of the complex QCD-vacuum structure. On the other side, we have developed new experimental tools in the form of nuclear relativistic beams, which allow to create rather extended regions in space-time of Hot Hadronic Matter. The confluence of these new and recent developments in theory and experiment led us to gather together from June 27 to July 1, 1994, at the Grand Hotel in Divonne-Ies-Bains, France, to discuss and expose the open questions and issues in our field.
The aim of this book is to offer to the next generation of young researchers a broad and largely self-contained introduction to the physics of heavy ion collisions and the quark-gluon plasma, providing material beyond that normally found in the available textbooks. For each of the main aspects - QCD thermodynamics and global features of the QGP, collision hydrodynamics, electromagnetic probes, jet and quarkonium production, color glass condensate, and the gravity connection - the present volume provides extensive and pedagogical lectures, surveying the present status of both theory and experiment. A particular feature of this volume is that all lectures have been written with the active assistance of selected students present at the course in order to ensure the adequate level and coverage for the intended readership.
