The properties of quantum chromodynamics (QCD), the modern theory of the strong interaction, can be investigated through the study of relativistic nucleus-nucleus collisions. Recently, the Relativistic Heavy-Ion Collider (RHIC) was completed and started taking data at ten times higher center-of-mass energies than the previous most energetic heavy-ion collisions. This thesis presents some of the first measurements at RHIC from any experiment. The PHOBOS detector is used to measure the charged particle pseudo-rapidity density at mid-rapidity (i.e., in [eta]

Furthermore, the pT dependence of the relative muon yields in Pb+Pb collisions to p+p colli- sions with the same center of mass collision energy per nucleon is presented by the nuclear modification factor RAA, which is defined as the ratio of a spectrum from heavy ion collisions to the same but scaled spectrum from nucleon-nucleon collisions . The observed RAA has little dependence on pT within the uncertainties quoted here. The results for RAA indicate a factor of about 3 suppression in the yield of muons in the most central (0-10%) collisions compared to the p+p collisions.

Papers of the June 1989 meeting in Beijing by the China Center of Advanced Science and Technology. This small book covers nucleus- nucleus collisions, states of the vacuum, and highly relativistic heavy ions in the experimental realm. Theoretical papers deal with quark-gluon plasma, and relativistic heavy ion collisions. Annotation copyrighted by Book News, Inc., Portland, OR

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.

The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at (square root)(s{sub NN}) = 19.6, 130 and 200 GeV. Two observations indicate universal behavior of charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/{bar p}p and ee− data. N{sub ch}/N{sub part}/2 in nuclear collisions at high energy scales with (square root)s in a similar way as N{sub ch} in ee− collisions and has a very weak centrality dependence. These features may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.

Doctoral Thesis / Dissertation from the year 2007 in the subject Physics - Nuclear Physics, grade: 1,0, University of Frankfurt (Main) (Institut für Kernphysik), language: English, abstract: Quarks sind die elementaren Bestandteile, aus denen Hadronen (Baryonen und Mesonen) aufgebaut sind. Zusammen mit den Leptonen und den Eichbosonen gelten sie heute als die fundamentalen Bausteine, aus denen alle Materie aufgebaut ist. Im Standardmodell der Teilchenphysik werden diese Ergebnisse zusammengefasst. Es gibt sechs verschiedene Quark-Arten (flavours): up, down, strange, charm, bottom und top. In der Natur kommen keine isolierten Quarks vor, sondern nur Kombinationen aus z.B. einem Quark-Antiquark Paar (Meson) oder aus drei Quarks (Baryon). Die Quantenchromodynamik (QCD) beschreibt die starke Wechselwirkung zwischen Quarks und Gluonen. Quarks bauen unter anderem Protonen und Neutronen auf. Gluonen vermitteln die Wechselwirkung zwischen den Quarks. Konzeptionell ist die QCD an die Quantenelektrodynamik (QED) angelehnt, die die Wechselwirkung elektrisch geladener Teilchen (z.B. Elektron oder Positron) durch den Austausch von Photonen beschreibt. Analog wirkt die Kraft, die durch den Austausch von Gluonen beschrieben wird, zwischen Teilchen, die eine Farbladung (rot, grün, blau) tragen. Im Vergleich zur QED, wo das Photon neutral ist, trägt das Gluon selbst Farbe und wechselwirkt daher mit anderen Gluonen. Bei kleinen Quarkabständen und hohen Energien bzw. hohen Impulsüberträgen, fällt die Kopplungskonstante der starken Wechselwirkung (αs) ab. Bei kleinem αs sind Quarks und Gluonen schwach gebunden (Asymptotische Freiheit). Bei grossen Abständen bzw. kleinen Impulsüberträgen ist αs gross. Die Zunahme von αs bewirkt, dass unendlich viel Energie benötigt wird, um Quarks aus Hadronen herauszulösen. Dies hat die Folge, dass es günstiger ist ein neues Quark-Antiquark Paar zu erzeugen. Das erklärt, warum Quarks immer in Hadronen (Mesonen und Baryonen) gebunden sind und nie isoliert beobachtet werden können (Confinement).Wenn Kernmaterie stark komprimiert wird, steigen Energiedichte und Temperatur, und möglicherweise erfährt die Kernmaterie einen Phasenübergang zu einem Zustand der als Quark Gluon Plasma (QGP) bezeichnet wird. Das QGP ist ein Zustand der Materie, in dem das Confinement der Quarks und Gluonen aufgehoben ist (Deconfinement). Dieser Zustand ist gekennzeichnet durch ein quasi-freies Verhalten der Quarks und Gluonen. Quarks und Gluonen in Hadronen ein. Im heutigen Universum existiert das QGP höchstens noch im Zentrum von Neutronensternen und explodierenden schwarzen Löchern.

This is a review volume containing articles written by experts on current theoretical topics in the subject of Quark-Gluon Plasma created in heavy-ion collisions at high energy. It is the fourth volume in the series with the same title sequenced numerically. The articles are written in a pedagogical style so that they can be helpful to a wide range of researchers from graduate students to mature physicists who have not worked previously on the subject. A reader should be able to learn from the reviews without having extensive knowledge of the background literature.

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.

One of few books to address both high-pT physics and relativistic heavy ion collisions. Essential handbook for graduates and researchers.

Here, elliptic flow (v2) values for identified particles at midrapidity in Au + Au collisions measured by the STAR experiment in the Beam Energy Scan at the Relativistic Heavy Ion Collider at √sNN = 7.7-62.4 GeV are presented for three centrality classes. The centrality dependence and the data at √sNN = 14.5 GeV are new. Except at the lowest beam energies, we observe a similar relative v2 baryon-meson splitting for all centrality classes which is in agreement within 15% with the number-of-constituent quark scaling. The larger v2 for most particles relative to antiparticles, already observed for minimum bias collisions, shows a clear centrality dependence, with the largest difference for the most central collisions. Also, the results are compared with a multiphase transport (AMPT) model and fit with a blast wave model.