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 Ups and Downs with a Bit of Strange written by Evan Warren Sangaline and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental results from the Relativistic Heavy Ion Collider (RHIC) Beam Energy Scan (BES) on identified particle spectra of [pi]+(−), K+(−), and p-(p) at mid-rapidity are presented. Au+Au collisions at center-of-mass energies of [squareroot]sNN=7.7, 11.5, 19.6, 27.0, 39.0, and 62.4 GeV are analyzed using data recorded by the Solenoidal Tracker at RHIC (STAR) detector. The resulting spectra are used to construct measurements of the nuclear modification factor R(CP), Bjorken energy density, and central event baryon enhancement as a function of collision energy. These measurements address the onset of deconfinement and help to bridge the gap between Super Proton Synchrotron (SPS) energies and top RHIC energy.
Download or read book Neutral Kaon Correlations in Au au Collisions at Center of Mass Energy of 200 GeV Per Nucleon Pair written by Selemon Bekele and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: A few microseconds after the Big Bang, the universe is believed to have existed in the form of a plasma composed of strongly interacting particles known as quarks and gluons. Although the quarks and gluons behave as asymptotically free particles in a Quark Gluon Plasma (QGP), free quarks and gluons have never been discovered in the laboratory. Experiments at the Relativistic Heavy Ion Collider (RHIC) aim to create conditions similar to the early universe by colliding heavy ions at the highest energies possible in the hope of observing a phase transition from a QGP into hadronic degrees of freedom. The response of the space time structure of the hot reaction zone created in a heavy ion collision to a phase transition is one of the many observables being studied at RHIC. Making use of the techniques of two particle intensity interferometry, also known as the HBT effect, the RHIC experiments are studying the space-time structure and dynamical properties of the region from which particles are emitted. A large spatial size and long duration of particle emission are the predicted signals for a phase transition from a QGP to a hadronic phase. In this thesis we present results on the first measurement of one dimensional K0[subscript s] K0[subscript s] interferometry by the STAR experiment at RHIC in central (small impact parameter) Au-Au collisions at center of mass energy of 200 GeV per nucleon pair. The lambda parameter, which is a measure of the sources chaoticity, is found to be consistent with unity confirming the fact that the source is mostly chaotic as measured by STAR using three particle correlations. Without taking into account the effect of the strong interaction, the invariant radius R inv is found to be large for the mean transverse mass M [subscript t] of the pair, which is about 980 MeV/c, compared to expectations from charged pion correlations at the same M [subscript t]. Including the effect of the strong interactions makes the radius parameter for the K0[subscript s] K0[subscript s] system fall within the charged pion M [subscript t] systematics. Our result serves as a valuable cross-check of charged pion measurements which are mainly affected by contributions from resonance decays and final state interactions. This is also an important first step towards a full three dimensional analysis of neutral kaon correlations as high statistics data from RHIC will be available in the near future.
Download or read book Large scale Two particle Correlation Sructures in Au Au Collisions at Center of Mass Energy written by Aya Ishihara and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Directed and Elliptic Flow in Au Au Collisions at a Center of Mass Energy of 19 6 GeV Per Nucleon nucleon Pair written by Michael George Anderson and published by . This book was released on 2006 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Using the Balance Function to Search for Late Hadronization in Au Au Collisions at a Center of Mass Energy of 130 GeV Per Nucleon Pair written by Marguerite Belt Tonjes and published by . This book was released on 2002 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pion Interferometry in AuAu Collisions at a Center of Mass Energy Per Nucleon of 200 GeV written by Mercedes López Noriega and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Quantum Chromodynamics predicts a phase transition from a state formed by hadrons to a plasma of deconfined quarks and gluons, the Quark Gluon Plasma, as a the energy density exceeds a critical value. This deconfined phase is believed to be the one in which the early universe existed in a time-scale [approx.] 10−5 s after the Big Bang. Ultrarelativistic Heavy Ion Collisions, like the ones that take place at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, reach energy densities above the critical value creating a deconfined phase of quarks and gluons that can be studied at the laboratory. This gives us the opportunity to study a phase of matter in the deconfined region of QCD, the properties of the strong interaction, the formation of hadronic matter and the interaction between hadrons. In the analysis presented in this thesis, the dynamical evolution of the particle emitting source and its space-time structure at freeze-out is studied using the two particle intensity interferometry technique. The expansion of the source is also studied. We find indications that this expansion may be caused by the initial pressure gradient generated in the initial stages of the collision through particle rescattering in a very dense medium.
Download or read book Elliptic Flow in Au Au Collisions at 200 GeV Per Nucleon Pair written by Carla Manuel Vale and published by . This book was released on 2004 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Relativistic Heavy Ion Collider (RHIC) has provided its experiments with the most energetic nucleus-nucleus collisions ever achieved in a laboratory. These collisions allow for the study of the properties of nuclear matter at very high temperature and energy density, and may uncover new forms of matter created under such conditions. This thesis presents measurements of the elliptic flow amplitude, v2, in Au+Au collisions at RHIC's top center of mass energy of 200 GeV per nucleon pair. Elliptic flow is interesting as a probe of the dynamical evolution of the system formed in the collision. The elliptic flow dependences on transverse momentum, centrality, and pseudorapidity were measured using data collected by the PHOBOS detector during the 2001 RHIC run. The reaction plane of the collision was determined using the multiplicity detector, and the azimuthal angles of tracks reconstructed in the spectrometer were then correlated with the found reaction plane. The v2 values grow almost linearly with transverse momentum, up to P[sub]T of approximately 1.5 GeV, saturating at about 14%. As a function of centrality, v2 is minimum for central events, as expected from geometry, and increases up to near 7% (for 0
Download or read book Transverse Energy Analysis of Au Au Collections at 7 7 11 5 19 6 27 and 39 GeV Through the Use of Identified Particles Spectra written by Biswas Sharma and published by . This book was released on 2018 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents an analysis of the transverse energy resulting from the collisions of gold nuclei at the Relativistic Heavy Ion Collider in Brookhaven National Laboratory. The transverse momentum distributions available from the STAR detector corresponding to nine different centralities for eight different identified particles, [pie]±̳ [pions, anti-pions], K±̳ [kaons, anti-kaons], [Lambda]±̳ [lambdas, anti-lambdas], p [protons], and p̅ [anti-protons], resulting from the collisions at five different center-of-mass energies per nucleon -- 7.7, 11.5, 19.6, 27, and 39 GeV -- are used in the calculations of the corresponding transverse energies. The results, when compared with the calorimetric transverse energy measurement from the PHENIX detector, show discrepancies of up to 2.83 [sigma] [standard deviations].
Download or read book Measurement of Charmed Meson Azimuthal Anisotropy in Au Au Collisions at a Center of Mass Energy of 200 GeV Per Nucleon Pair at RHIC written by Michael Richard Lomnitz and published by . This book was released on 2016 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Charged Kaon Production in Au Au Collisions at center of mass Energy Per Nucleon Pair written by Wensheng Deng and published by . This book was released on 2002 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Trotsky jug par L nine textes et documents choisis par M S Olminsky en opposition Trotsky written by and published by . This book was released on 1925 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book J Psi E e Measurements in Cu Cu Collisions at 200 GeV written by Kushal Das and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: J/Psi production has been measured by the PHENIX experiment, one of the two major experiments at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) in p + p, d + Au, Au + Au and Cu + Cu collisions at the center of mass energy per nucleon (sqrt {s_{NN}}) of 200 GeV. The analysis of the Cu + Cu data is the focus of this dissertation.
Download or read book Energy Dependence of K P and Kp Fluctuations in Au Au Collisions from u221A sNN written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for the quantum chromodynamics (QCD) critical point was performed by the STAR experiment at the Relativistic Heavy Ion Collider, using dynamical fluctuations of unlike particle pairs. Heavy ion collisions were studied over a large range of collision energies with homogeneous acceptance and excellent particle identification, covering a significant range in the QCD phase diagram where a critical point may be located. Dynamical K?, p?, and Kp fluctuations as measured by the STAR experiment in central 0–5% Au+Au collisions from center-of-mass collision energies √sNN=7.7 to 200 GeV are presented. The observable ?dyn was used to quantify the magnitude of the dynamical fluctuations in event-by-event measurements of the K?, p?, and Kp pairs. The energy dependences of these fluctuations from central 0–5% Au+Au collisions all demonstrate a smooth evolution with collision energy.
Download or read book Measurement of Heavy Flavor Yield and Azimuthal Anisotropy at Forward Angles in Cu Au Collisions at a Center of mass Collision Energy Per Nucleon of 200 GeV written by Brandon Kyle Schmoll and published by . This book was released on 2017 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heavy flavor quarks are produced early in heavy ion collisions and will experience the full evolution of the Quark Gluon Plasma (QGP). Measurements at forward rapidity may be influenced as much, or more, by the cold nuclear matter effects as by the hot nuclear matter effects associated with a QGP. As the medium evolves, the initial spatial anisotropy of participants is converted to an azimuthal anisotropy in the momentum space of outgoing particles. Therefore, the momentum spectra modification and anisotropy parameters provide useful information about the heavy quark interaction with the bulk medium. Asymmetric heavy ion collisions, such as Cu+Au, provide a unique geometry with which to study the dynamics of the heavy quarks, relative to that in symmetric collisions. In particular, asymmetries in the yields between the Cu-going and Au-going directions may help unentangle the so-called cold nuclear matter effects from the hot nuclear matter effects indicative of a QGP. In addition, the parameters v2 and v3 in asymmetric collisions may be modified relative to the symmetric collisions due to the unique geometry provided in mid-central Cu+Au collisions. This dissertation presents the measurement of the yield and azimuthal anisotropy of single muons originating from heavy flavor decays in [square root of]SNN [center-of-mass energy per nucleon] = 200 GeV Cu+Au collisions.
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:
