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Dissertations / Theses on the topic 'Montecarlo for heavy-ion collisions'

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Published: 10 March 2023

Last updated: 11 March 2023

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1

Valerio, Peter Michael 1968. "Heavy quark production in heavy-ion collisions." Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/288922.

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The results of the full next-to-leading-order calculation of open charm production cross section, via hard parton scattering, for both hadronic and heavy-ion collisions at RHIC and LHC energies are presented. In addition to the total cross section, the transverse momentum and rapidity distributions are included. An effective K-factor which encapsulates the next-to-leading-order corrections and the nuclear effects is presented. The open charm yield will be measured through the correlated dileptons produced when the charm decays. An important background comes from the decay of bottom quarks. Therefore, the open bottom yield from hard parton scatterings is presented. The first next-to-leading-order calculation of the thermal heavy quark production is presented, as well as the dimuon spectrum from both the thermal and the initial fusion charm and bottom production at RHIC energies.

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2

Nesbitt, Brian. "Heavy-particle collisions." Thesis, Queen's University Belfast, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301028.

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3

Pandit, Yadav. "AZIMUTHAL ANISOTROPY IN HEAVY ION COLLISIONS." Kent State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=kent1353871180.

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4

Taliotis, Anastasios Socrates. "Geometrical Methods in Heavy Ion Collisions." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1285088429.

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5

Stockmeier, Marc R. "Pion production in relativistic heavy ion collisions." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965097234.

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6

Qin, GuangYou. "Penetrating probes in relativistic heavy ion collisions." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115878.

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In this dissertation, the phenomenology of electromagnetic radiation and high transverse momentum jets in relativistic heavy ion collisions is investigated. These are two very important probes to study the strongly interacting matter at extreme temperatures and/or densities and to investigate the possibility of a phase transition between hadronic matter and quark-gluon plasma (QGP). First, a new channel of direct photon production from a charge-asymmetric QGP is explored in the effective theory of quantum chromodynamics (QCD) at high temperature. The photon production from this new channel is found to be suppressed compared to QCD annihilation process and Compton scattering at low baryon density, but might assume significance in baryon-rich matter. Second, the radiative jet energy loss in a three-dimensional ideal hydrodynamical medium is studied for Au+Au collisions at Relativistic Heavy Ion Collider (RHIC). A systematic analysis of the nuclear modification factor RAA is presented for pi0 production at high pT in central and non-central collisions, at mid and forward rapidity. Third, jet energy loss by elastic collisions is consistently incorporated in the same formalism and applied to the study of jet quenching at RHIC. It is found that the nuclear modification factor RAA for pi0 in relativistic heavy ion collisions is sensitive to both collisional and radiative energy loss, while the average energy loss is less affected by the inclusion of collisional energy loss. Last, the nuclear suppression of photon-tagged jets at high pT is studied by incorporating not only direct photons, but the additional sources from fragmentation and jet-plasma interaction. We find that these additional sources are very important for a complete study of the correlations between hard photons and hadrons and even dominate in some kinetic regime.

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7

Mazeliauskas, Aleksas. "Fluctuations in Ultra-Relativistic Heavy Ion Collisions." Thesis, State University of New York at Stony Brook, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10256734.

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<p> Fluctuations are one of the main probes of the physics of the new state of hot and dense nuclear matter called the Quark Gluon Plasma (QGP) which is created in the ultra-relativistic heavy ion collisions. In this dissertation we extend and improve upon the existing descriptions of heavy ion collisions in three different directions: we study the new signatures of initial state fluctuations, the propagation of perturbations in the early stages of the collision, and the effect of thermal fluctuations on the hydrodynamic expansion of the QGP. </p><p> First, in Chapter 3 we study initial state fluctuations by examining the complete statistical information contained in the two-particle correlation measurements in hydrodynamic simulations of Pb+Pb collisions at the CERN Large Hadron Collider (√<i>s<sub>NN</sub></i> = 2.76 TeV). We use Principal Component Analysis (PCA) to decompose the spectrum of harmonic flow, v_n(p_T) for <i>n</i> = 0–5, into dominant components. The leading component is identified with the standard event plane <i> v<sub>n</sub></i>(<i>p<sub>T</sub></i>), while the subleading component describes additional fluctuations in the two-particle correlation function. We find good geometric predictors for the orientation and the magnitude of the leading and the subleading flows. The subleading <i>v</i><sub> 0</sub>, <i>v</i><sub>1</sub>, and <i>v</i><sub>3</sub> flow harmonics are shown to be a response to the radial excitation of the corresponding eccentricity ϵ<i><sub>n</sub></i>. In contrast, for <i>v</i><sub>2</sub> the subleading flow in peripheral collisions is dominated by the nonlinear mixing between the leading elliptic flow and radial flow fluctuations. Nonlinear mixing also plays a significant role in generating subleading <i>v</i><sub>4</sub> and <i>v</i><sub> 5</sub> harmonics. The PCA gives a systematic way of studying the full information of the two-particle correlation matrix and identifying the subleading flows, which we show are responsible for factorization breaking in hydrodynamics. </p><p> Second, in Chapter 4 we study the thermalization and hydrodynamization of fluctuations at the early stages of heavy ion collisions. We use leading order effective kinetic theory, accurate at weak coupling, to simulate the pre-equilibrium evolution of transverse energy and flow perturbations. For the short evolution we can use a linear response theory to construct the pre-equilibrium Green functions. Then the energy-momentum tensor at a time when hydrodynamics becomes applicable can be expressed as a linear convolution of response functions with the initial perturbations. We propose combining effective kinetic theory with weak coupling initial state models, such as IP-Glasma, to model the complete pre-thermal evolution from saturated nuclei to hydrodynamics in a weak coupling framework. </p><p> Last, in Chapter 5 we consider out-of-equilibrium hydrodynamic fluctuations in the expanding QGP. We develop a set of kinetic equations for a correlator of thermal fluctuations which are equivalent to nonlinear hydrodynamics with noise. We first show that the kinetic response precisely reproduces the one-loop renormalization of the shear viscosity for a static fluid. We then use the hydro-kinetic equations to analyze thermal fluctuations for a Bjorken expansion. The steady state solution to the kinetic equations determine the coefficient of the first fractional power of the gradient expansion (∞ 1/(τ<i> T</i>)<sup>3/2</sup>), which was computed here for the first time. The formalism of hydro-kinetic equations can be applied to more general background flows and coupled to existing viscous hydrodynamic codes to incorporate the physics of hydrodynamic fluctuations.</p><p>

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8

Gale, Charles 1957. "Macroscopic and microscopic aspects of heavy ion collisions." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=73975.

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9

Renk, Thorsten. "QCD matter under extreme conditions heavy ion collisions /." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=966327764.

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10

Tabti, Rahma. "Soft dilepton production in ultrarelativistic heavy-ion collisions." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23428.

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We investigate and compare two field theoretical formalisms, namely, the former state-of-the-art but noncovariant Ruckl formula-based formalism developed by K. Haglin and C. Gale, and a more recent covariant formalism developed by P. Lichard, for lepton pair production via soft virtual bremsstrahlung in hadronic reactions. A quantitative study of the discrepancy between both formalisms with regard to rates and total yields of $e sp{+}e sp{-}$ and $ mu sp{+} mu sp{-}$ pair production from radiative pion and quark (antiquark) scattering in ultrarelativistic heavy-ion collisions is made. Dilepton production rates are calculated using the independent particle approximation from kinetic theory, and total dilepton yields are obtained by integrating these rates over the space-time evolution of the heavy-ion collision as dictated by Bjorken's longitudinal hydrodynamic model. All rates and total yields of $e sp{+}e sp{-}$ and $ mu sp{+} mu sp{-}$ pair production with invariant masses less than 300 MeV turn out to be overestimated in the Ruckl formula-based formalism.

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11

Bertrand, Martine 1976. "Photon production in high energy heavy ion collisions." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31196.

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The production of photons in the energy range of 0 to 3 GeV is discussed as a signature of the creation of a quark-gluon plasma in ultrarelativistic nuclear collisions. However, they are also created in the hadronic phase. Therefore I investigate the role of the pirho → pigamma and pio → pigamma reactions in the photon emission from hot hadronic matter, and I compare their respective importance. These reactions are known to be the leading contributions. For this purpose I use diverse effective chiral Lagrangians that are in accord with known empirical properties of strong interaction. Then I discuss the relevance of my work to heavy ion collisions.

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12

Song, Huichao. "Causal Viscous Hydrodynamics for Relativistic Heavy Ion Collisions." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1250542758.

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13

Wertepny, Douglas E. "Two-Particle Correlations in Heavy-Light Ion Collisions." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1468596055.

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14

Wong, Michael. "Evolution of anisotropies in asymmetric heavy ion collisions." Connect to resource, 2009. http://hdl.handle.net/1811/37002.

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15

Devismes, Anne. "K+ production in heavy ion collisions at 1.5 AGeV." [S.l.] : [s.n.], 2000. http://elib.tu-darmstadt.de/diss/000154/these.pdf.

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16

Barton, Robert Allan. "Multi-strange hyperon production in relativistic heavy -ion collisions." Thesis, University of Birmingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367744.

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17

Ritchie, Robert Alexander. "J/Ψ suppression in ultra-relativistic heavy ion collisions". Thesis, University of Cape Town, 1990. http://hdl.handle.net/11427/26225.

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18

Alqahtani, Mubarak Aydh K. "QUASIPARTICLE ANISOTROPIC HYDRODYNAMICS IN ULTRA-RELATIVISTIC HEAVY-ION COLLISIONS." Kent State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=kent1512385855986591.

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19

Frodermann, Evan S. "A view of heavy-ion collision dynamics and geometry through electromagnetic signatures." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1219089772.

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20

Brunne, Carl Ludwig Tim. "Charge transfer and pair production in relativistic heavy-ion collisions." [S.l. : s.n.], 2001. http://www.diss.fu-berlin.de/2001/123/index.html.

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21

Fillion-Gourdeau, François. "Applications of many-body physics to relativistic heavy ion collisions." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40754.

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In this dissertation, many-body physics techniques are used to study and improve ideas related to the description of heavy ion collisions at very high energy. The first part of the thesis concerns the production of tensor mesons in proton-proton (pp) collisions. An effective theory where the f2 meson couples to the energy-momentum tensor is proposed and a comparison of the inclusive cross-section computed in the collinear factorization, the kT-factorization and the color glass condensate is performed. A study of the phenomenology in pp collisions then shows a strong dependence on the parametrization of the unintegrated distribution function. The conclusion is that f2 meson production can be utilized to improve the understanding of the proton wave-function. In the second part, a similar investigation is performed by analysing the production cross-section of the eta' meson in pp and proton-nucleus (pA) collisions. The nucleus and proton are described by the CGC and the kT-factorization respectively. A new technique for the computation of Wilson lines - color charge densities correlators in the McLerran-Venugopalan model is developped. The phenomenology shows that the cross-section in pA collisions is very sensitive to the value of the saturation scale, a crucial ingredient of the CGC picture. In the third part of the thesis, the collision term of the Boltzmann equation is derived from first principles at all orders and for any number of participating particles, starting from the full out-of-equilibrium quantum field theory and using the multiple scattering expansion. Finally, the emission of photons from a non-abelian strong classical field is investigated. A formalism based on Schwinger-Keldysh propagators relating the production rate of photons to the retarded solution of the Dirac equation in a background field is presented.<br>Dans cette dissertation, les techniques de la physique à plusieurs corps sont utilisées afin d'étudier et d'améliorer certaines idées reliées à la description des collisions d'ions lourds à haute énergie. La première partie de cette thèse s'intéresse à la production des mésons tenseurs dans les collisions proton-proton (pp). Une théorie effective où le méson f2 couple avec le tenseur énergie-impulsion est proposée et une étude comparative de la section efficace calculée dans les formalismes de la factorisation colinéaire, de la factorisation-kT et du color glass condensate (CGC) est entreprise. La phénoménologie dans les collisions pp montre que la section efficace est très sensible à la paramétrisation des fonctions de distribution non-intégrées. En conséquence, la production de mésons f2 peut être utilisée pour améliorer notre compréhension de la fonction d'onde du proton. Dans la seconde partie, une investigation similaire est entreprise où la section efficace de production de mésons eta' est analysée dans les collisions pp et proton-noyau (pA). Le noyau et le proton sont décrits par le CGC et la factorisation-kT respectivement. Une nouvelle technique pour le calcul des correlateurs de lignes de Wilson - densités de charge de couleur dans le modèle de McLerran-Venugopalan est développée. La phénoménologie nous démontre ensuite que la section efficace dans les collisions pA est très sensible à la valeur de l'échelle de saturation, qui est un des éléments crucial dans l'approche du CGC. Dans la troisième partie de cette thèse, le terme de collision de l'équation de Boltzmann est dérivé à partir de principes premiers en utilisant l'expansion en collisions multiples. Finalement, l'émission de photons à partir d'un champs non-abélien classique fort est étudiée. Un formalisme basé sur les propagateurs de Schwinger-Keldysh et qui relie le taux de production des photons à la solution retardée de l'équa

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22

Marquardt, Ronald Richard. "Strangeness production via pion rescattering in ultrarelativistic heavy-ion collisions." Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/17237.

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23

Adams, Rory Montague. "Flux corrected transport applied to hydrodynamics for heavy ion collisions." Doctoral thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/6521.

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Includes abstract.<br>Includes bibliographical references (p.145-154).<br>This thesis presents FCTHydro, a ROOT package, and its application to hydrodynamic simulations through the packages RelHydro and Nonideal xy. These packages aim to provide the broader heavy ion collision community with access to hydrodynamic simulation software which is now accessible from within the primary analysis framework, ROOT. Tests are performed and show how well the high-order, monotone, conservative, positivity preserving routines within FCTHydro simulate hydrodynamic systems with harsh initial conditions. RelHydro illustrates the application of FCTHydro to relativistic systems and Nonideal xy the application to causal non-ideal hydrodynamic systems. Nonideal xy is also used to obtain a first order understanding of the effects of the relaxation times in causal non-ideal hydrodynamics. In addition, a semi-analytic solution for the particle rapidity spectra obtained by combining Landau hydrodynamics and the Cooper-Frye freezeout formalism is given. The results are compared with the Landau Gaussian and a known approximation for midrapidies. The Landau Gaussian provides the best approximation to experimental data. Furthermore, the chemical freezeout results for preliminary data from AGS for central Au-Au collisions at nominal beam energies 2, 4, 6 and 8 AGeV are shown to agree with the E/N = 1 GeV freezeout criteria. These data allow access to a previously unexplored region in the T-μB phase space.

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24

Qiu, Zhi. "Event-by-event Hydrodynamic Simulations for Relativistic Heavy-ion Collisions." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1375890576.

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25

Abu-Samreh, Mohammad Mahmud. "Thermalization theory in heavy ion collisions by nonequilibrium statistical mechanics." Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185391.

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This dissertation presents a semiclassical microscopic approach based on the Uehling-Uhlenbeck equation for studying the equilibration processes due to nucleon-nucleon collisions during the collision of two heavy ions in the low and intermediate energy domain (5-100 MeV/nucleon). The state formed in the early stages of a heavy-ion collision can be characterized by a highly excited non-equilibrium system of nucleons. Equilibration processes then take place resulting in a system for which a temperature can be defined at least locally. The single-nucleon distribution function for the nucleons during the early stage of the ion-ion collision is represented in momentum-space either by two Fermi-spheres separated by the relative momentum of the impacting ions or by a deformed Fermi-sphere. The equilibration (thermalization) of this initial distribution in momentum-space is studied by calculating the collision term as a function of time. The relaxation-times are investigated through a microscopic model that incorporates the UU collision term with the relaxation-time approximation. Relaxation-times for the equilibration are obtained as a function of density and temperature. The temperature dependence is strong at low temperatures and this is a consequence of the Fermi statistics. The mode dependence of the relaxation-times is also calculated by expanding the angular dependence of the distribution in spherical harmonics. The RTA is also tested against thermalization of the Fermi-sphere systems and is found to be reasonable. Transport coefficients for viscosity, thermal conductivity and diffusion are also calculated as well as their temperature and density dependencies. Their relation to relaxation-times are derived. The mean free path of nucleons in hot nuclear matter is also studied in the same frame of work. The numerical calculations of the collision term are an important part of this investigation. They involve five-dimensional integrations carried out using Gaussian and Simpson's numerical methods.

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26

Hewitt, Robin Nicholas. "An L² representation of the continuum in heavy particle collisions." Thesis, Durham University, 1987. http://etheses.dur.ac.uk/6770/.

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This thesis is concerned with the use of L² or square integrable functions as a representation of the electronic continua in ion-atom collisions. An exact representation of the continuum states is considered for comparison. The functions are optimised in an attempt to remove some of the arbitrary features present in such calculations. The original work of this thesis is mainly concerned with the calculation of single electron processes in collisions between He²⁺ ions and neutral lithium atoms. The cross sections for single electron capture were calculated in a close-coupled approximation, using the semi-classical impact parameter method. A maximum of thirty-two atomic orbitals with plane-wave translational factors attached were centred upon the target and projectile. Satisfactory agreement with experimental data is obtained over the He(^2+)laboratory energy range from 8 to 2000 keV. The results show the importance of the continuum over a restricted range of impact energies. The rest of the research is concerned with direct excitation and ionisation in the same collision system and results are given for He²⁺ laboratory energies between 20 and 6000 keV. The calculations used a similar close-coupled approximation with up to sixty-five basis states. The best ionisation cross sections reproduce the experimental data apart from a normalization factor. The excitation results were more sensitive to basis set choice. The ionisation cross sections were also investigated using an exact representation of the continuum states, using the First Born Approximation and a t-matrix approximation in an attempt to improve upon the L² results. The relationship between the present calculations and some previous methods are discussed and suggestions for future work are made. These are the first close-coupled estimates of ionisation for this sytem and show that contributions from target d- and f- states dominate the ionisation cross section around its maximum.

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Planells, Noguera Xumeu. "Searching for P- and CP- odd effects in heavy ion collisions." Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/284646.

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In this thesis we study the possibility that QCD breaks parity at high temperatures and densities, a scenario that may be tested in heavy ion collisions. We present two different approaches to this problem. On the one hand, analytical studies with effective models suggest that QCD may break parity in dense systems due to condensation of pseudoscalar mesons in the isotriplet channel. On the other hand, P- and CP- odd bubbles may appear in a finite volume due to local large topological fluctuations in a hot medium. The presence of a large magnetic field or angular momentum may lead to the so-called Chiral Magnetic Effect. We assume topological fluctuations as the source of parity violation in heavy ion collisions throughout. This effect may be treated in a quasi-equilibrium description by means of a non-trivial axial chemical potential. We consider the 'two flavour' Nambu—Jona-Lasinio model in the presence of a vector and an axial external chemical potentials and study the phase structure of the model at zero temperature. The Nambu—Jona-Lasinio model is often used as a toy replica of QCD and it is therefore interesting to explore the consequences of adding external vector and axial chemical potentials in this model, mostly motivated by claims that such external drivers could trigger a phase where parity could be broken in QCD. We are also motivated by some lattice analysis that attempt to understand the nature of the so-called Aoki phase using this simplified model. Analogies and differences with the expected behaviour in QCD are discussed and the limitations of the model are pointed out. We also consider the low energy realization of QCD in terms of mesons when an axial chemical potential is present; a situation that may be relevant in heavy ion collisions. We demonstrate that the presence of an axial charge has profound consequences on scalar/pseudoscalar meson physics. The most notorious effect is the appearance of an explicit source of parity breaking. The eigenstates of strong interactions do not have a definite parity and interactions that would otherwise be forbidden compete with the familiar ones. We focus on scalars and pseudoscalars that are described by a generalized linear sigma model. We comment briefly on the screening role of axial vectors in formation of effective axial charge and on the possible experimental relevance of our results, whose consequences may have been already seen at RHIC. Finally, we investigate how local parity breaking may affect vector physics. A modified dispersion relation is derived for the lightest vector mesons rho and omega. They are characterised by a mass splitting depending on their polarization. This effect predicts a natural overproduction of lepton pairs in the vicinity of the rho-omega resonance peak as well as a polarization asymmetry around this peak. The dilepton excess seems relevant to explain the anomalous dielectron yield quoted by PHENIX/STAR. We present a detailed analysis of the angular distribution associated to the lepton pairs created from these mesons searching for polarization dependencies. Two angular variables are found to carry the main information related to the parity-breaking effect. Possible signatures for experimental detection of local parity breaking are discussed.<br>En esta tesis estudiamos la posibilidad de que QCD rompa paridad a altas temperaturas y densidades, un escenario que se puede examinar en colisiones de iones pesados. Estudios analíticos con modelos efectivos sugieren que QCD puede romper paridad en sistemas densos. Además, pueden aparecer burbujas con P y CP impar en un volumen finito debido a grandes fluctuaciones topológicas locales en un medio caliente. Este último efecto puede ser tratado en una descripción cercana al equilibrio mediante un potencial químico axial. Consideramos el modelo de Nambu—Jona-Lasinio con ‘dos sabores’ en presencia de un potencial químico vectorial y uno axial y estudiamos la estructura de fases del modelo a temperatura cero. Estas magnitudes podrían abrir una fase donde la paridad podría romperse en QCD. También nos motivan algunos análisis en el retículo que intentan entender la naturaleza de la llamada fase de Aoki usando este modelo simplificado. Se discuten analogías y diferencias con el comportamiento esperado en QCD además de las limitaciones del modelo. Consideramos también la realización de QCD a bajas energías en términos de mesones en presencia de un potencial químico axial. Demostramos que la presencia de una carga axial tiene profundas consecuencias en la física de mesones escalares y pseudoescalares. Los autoestados de la interacción fuerte no tienen una paridad bien definida y en consecuencia, algunas interacciones antes prohibidas, ahora compiten con las más familiares. Nos centramos en escalares y pseudoescalares que se describen mediante un modelo sigma lineal generalizado. Finalmente, investigamos cómo la ruptura de paridad local puede afectar la física de mesones vectoriales. Se deriva una relación de dispersión modificada para los mesones más ligeros rho y omega. Este efecto predice una sobreproducción natural de parejas de leptones en las inmediaciones del pico de resonancia rho-omega así como una asimetría en la polarización alrededor de este pico. El exceso de dileptones parece ser relevante para explicar la producción anómala de dielectrones citada por PHENIX/STAR. Presentamos un análisis detallado de la distribución angular asociada a las parejas de leptones creadas de estos mesones en busca de dependencias en la polarización. Se encuentran dos variables angulares que transportan la información principal relacionada con el efecto de ruptura de paridad.

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Soff, G., Burkhard Kämpfer, M. Hentschel, André Peshier, and O. P. Pavlenko. "Electromagnetic signals from deconfined matter resulting from ultrarelativistic heavy-ion collisions." Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-31513.

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Yilmaz, Yetkin. "Jet quenching in heavy-ion collisions at LHC with CMS detector." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/83816.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2013.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 143-148).<br>The collision of highly relativistic nuclei can produce a volume of high energy density which can be used to learn about the behavior of quantum chromodynamics (QCD) at extreme conditions, such as those of the universe at times before and during the formation of hadrons out of quarks and gluons. This thesis presents experimental studies of jet-quenching phenomena in PbPb collisions at [square root of]sNN = 2.76 TeV, with a focus on the study of the energy-loss, namely the analysis of correlations of jet pairs as measured by the CMS detector at LHC. The implications of the results are discussed by comparison of simple models with data. It is observed that the geometrical configuration of the dijets and the nuclear collision region plays an important role in the correlations between the jets, and the set of CMS results reviewed can illustrate the dependence of the amount of lost energy on the length of the traversed medium.<br>by Yetkin Yilmaz.<br>Ph.D.

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30

Park, Youngsoo. "Centrality dependence of two-particle correlations in relativistic heavy ion collisions." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/51591.

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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2009.<br>Includes bibliographical references (p. 63-64).<br>Results on the centrality dependence of two-particle correlations in Au+Au collisions at ... 200GeV are presented. A particular focus is devoted to investigating any anomalous behavior in the centrality dependence of correlation functions, as previous results suggest existence of such tendencies around Npart [approx.] 50. Correlation functions are calculated for a wide kinematic region of ... from data obtained by the PHOBOS experiment at RHIC. The RHIC layout and the PHOBOS detector setup is discussed. Data acquisition method employed by the PHOBOS experiment, data processing procedures and event selection criteria are presented. The two-particle correlation function is defined and calculation procedures are described. Decomposition analysis is explained as the fit function and the constituting components are introduced. Analysis results for correlation functions and fits are presented. The results suggest that in the kinematic region covered by the analysis of this thesis, no anomalous trends in component behavior exists.<br>by Youngsoo Park.<br>S.B.

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31

Soff, G., Burkhard Kämpfer, M. Hentschel, André Peshier, and O. P. Pavlenko. "Electromagnetic signals from deconfined matter resulting from ultrarelativistic heavy-ion collisions." Forschungszentrum Rossendorf, 1996. https://hzdr.qucosa.de/id/qucosa%3A21977.

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32

Razak, Nawahl. "Maxima in strangeness observed in heavy ion collisions using statistical models." Master's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/6549.

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Includes bibliographical references (leaves 47-50).<br>Nucleus-Nucleus collisions enable the heating and compression of nuclei in order to probe matter under extreme temperature and energy density. With a resonance gas mode, of hadronic matter, Hagedorn came to the conclusion that on increasing the energy density, hadronic matter could exist above a limiting temperature of appriximately 160 MeV. Above this temperature it is expected that hadronic matter undergoes a phase transition to a state of deconfined fundamental quarks and gluons known as quark gluon plasma (QGP).

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33

Shen, Chun. "The standard model for relativistic heavy-ion collisions and electromagnetic tomography." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1405931790.

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34

Hencken, Kai. "Electromagnetic production of electron positron pairs in relativistic heavy ion collisions." [S.l.] : [s.n.], 1994. http://edoc.unibas.ch/diss/DissB_3179.

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35

Riley, Charles Kent. "Searching for Local Parity Violation in Heavy Ion Collisions at STAR." Thesis, Yale University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3578440.

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<p>Quantum chromodynamics (QCD) is the theory that concerns how the strong force interacts with subatomic particles. Topological configurations that interpolate between vacuum states have been shown to play an important role in the quark-gluon plasma (QGP), believed to be created in heavy ion collisions. The possible existence of [special characters omitted]-odd domains in the QGP combined with an external magnetic field that is produced in mid-central collisions may be the ingredients necessary for the so-called chiral magnetic effect (CME). The CME is the consequence of topological features called sphalerons (that are created in the hot QCD matter) in the presence of a strong magnetic field, and it induces a separation of negatively and positively charged particles along the direction of the field. This separation varies its orientation from event to event, resulting in the expectation value of any [special characters omitted]-odd observable to vanish, making it necessary to measure the variation in fluctuations. Any indication of a real charge dipole moment could be evidence for local parity violation (LPV), which would have profound implications on our understanding of the natural world.</p><p> In this dissertation, charge dependent azimuthal correlations are used to measure the charge separation fluctuations in gold ion collisions at STAR. There are three primary analyses: measuring charge distributions as a function of beam energy, by selecting specific hadron species to filter background effects, and for uranium ion collisions. The beam energy analysis shows that a small charge separation shrinks with diminishing beam energy, eventually vanishing at the lowest energies. The kaon-pion correlations are performed to eliminate specific background effects unrelated to the CME, and behave consistently with results using all types of hadrons. The uranium analysis attempts to distinguish how much of the azimuthal correlations are influenced by elliptic anisotropy, suggesting the signal is coming from a mixture of CME and strong interaction backgrounds. From the evidence gathered from these analyses, we conclude that there are signs of small charge separations congruous to predictions from the CME, however, much of the signal is obscured by other strong interaction backgrounds. The effective contribution strengths are calculated and suggestions for improvements are made in the conclusion.</p>

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36

Kuhlman, Anthony Joseph. "The beginning and end of relativistic heavy ion collisions using uranium beams and Bose-Einstein correlations as probes of the collision fireball /." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1185456181.

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37

Khudeir, Imad. "Scattering of polarized lithium-7 form nuclei at energies near the Coulomb barrier." Thesis, University of Strathclyde, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292177.

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38

Hering, Gunar. "Dielectron production in heavy ion collisions at 158 GeV-c per nucleon." [S.l.] : [s.n.], 2001. http://elib.tu-darmstadt.de/diss/000196.

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39

Hentschel, M., O. P. Pavlenko, K. Redlich, G. Soff, and Burkhard Kämpfer. "Diphoton rates from thermalized matter resulting in ultra-relativistic heavy-ion collisions." Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-31470.

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Diphoton radiation off strongly interacting matter resulting from ultrarelativistic heavy-ion collisions is estimated for SPS and RHIC conditions. At SPS emrgies tha thermal diphoton signal competes strongly with the Drell - Yan like background. For given charged-particle rapidity density a scenario with deconfinement transition predicts a larger diphoton yield than a scenario without phase transition. For RHIC energies we find that radiation from initially undersaturated (but gluon-rich) deconfined matter overwhelms the hadron gas and the Drell - Yan like diphotons in the invariant mass window 1 < M < 2.5 GeW. Due to this the so-called M1 scaling is approximately obtained and can serve as additional tsol for discriminating radiation from quark-gluon matter.

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40

Persram, Declan. "A momentum-dependent lattice Hamiltonian model for simulations of heavy ion collisions /." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=37811.

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We investigate both directed and elliptic flow and linear momentum transfer in intermediate energy heavy ion collisions. The model that we have adapted for this work is the BUU transport equation solved with a momentum-dependent lattice Hamiltonian algorithm. We introduce an extension of this transport model that consistently takes into account the momentum-dependent in-medium modification of the nucleon-nucleon collision cross section. Comparison with linear momentum transfer data favours a soft momentum-dependent nuclear mean field of compressibility K = 215 MeV. Analysis of higher energy elliptic flow data favours a momentum-dependent over that of a momentum-independent nuclear mean field. Furthermore, we find that both the linear momentum transfer and elliptic flow data favour an in-medium nucleon-nucleon cross section over the free space cross section.

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41

Ma, Frank Teng. "Detailed characterization of jets in heavy ion collisions using jet fragmentation functions." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/83823.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2013.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 159-163).<br>In this thesis the jet fragmentation function of inclusive jets with transverse momentum PT > 100 GeV/c in PbPb collisions is measured for reconstructed charged particles with PT > 1 GeV/c within the jet cone. A data sample of PbPb collisions collected in 2011 at a center-of-mass energy of [square root of]sNN = 2.76 TeV corresponding to an integrated luminosity of 150 [mu]b-1 is used. The results for PbPb collisions as a function of collision centrality are compared to reference distributions based on pp data collected at the same collision energy. A centrality-dependent modification of the fragmentation function is revealed. For the most central collisions a significant enhancement is observed in the PbPb/pp fragmentation function ratio for the charged particles with PT less than 3 GeV/c.<br>by Frank Teng Ma.<br>Ph.D.

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42

Hentschel, M., O. P. Pavlenko, K. Redlich, G. Soff, and Burkhard Kämpfer. "Diphoton rates from thermalized matter resulting in ultra-relativistic heavy-ion collisions." Forschungszentrum Rossendorf, 1996. https://hzdr.qucosa.de/id/qucosa%3A21974.

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Abstract:

Diphoton radiation off strongly interacting matter resulting from ultrarelativistic heavy-ion collisions is estimated for SPS and RHIC conditions. At SPS emrgies tha thermal diphoton signal competes strongly with the Drell - Yan like background. For given charged-particle rapidity density a scenario with deconfinement transition predicts a larger diphoton yield than a scenario without phase transition. For RHIC energies we find that radiation from initially undersaturated (but gluon-rich) deconfined matter overwhelms the hadron gas and the Drell - Yan like diphotons in the invariant mass window 1 < M < 2.5 GeW. Due to this the so-called M1 scaling is approximately obtained and can serve as additional tsol for discriminating radiation from quark-gluon matter.

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43

Powell, Christopher Beresford. "J / ( ) production in heavy ion collisions at the STAR detector at RHIC." Doctoral thesis, University of Cape Town, 2012. http://hdl.handle.net/11427/6546.

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Includes abstract.<br>Includes bibliographical references.<br>The success of the Standard Model of particle physics in describing a large variety of experimental results has been supported by the prediction and subsequent discovery of the charm, bottom, and top quarks, and the Z, W±, and Higgs bosons. The theory of Quantum Chromodynamics (QCD), which describes the strong interaction between quarks and gluons in the Standard Model, predicts a phase transition from hadronic matter to a deconfined Quark Gluon Plasma (QGP) at high temperature and energy density. The Relativistic Heavy Ion Collider (RHIC) was built to achieve these conditions to test the predictions of QCD and understand the properties of a deconfined medium. Charm (c) quarks have been suggested as ideal probes of the medium created in heavy ion collisions, as they are created primarily in the initial hard scattering of the collision because of their large mass.

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44

Bacquias, Antoine. "Kinematical properties of spectator fragments in heavy-ion collisions at relativistic energies." Université Louis Pasteur (Strasbourg) (1971-2008), 2008. https://publication-theses.unistra.fr/public/theses_doctorat/2008/BACQUIAS_Antoine_2008.pdf.

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Heavy-ion collisions at relativistic energies are the main tool to reach extreme conditions of temperature and density with the nuclear matter. The geometry of the collisions defines the “spectator” matter (formed by residues from projectiles) by contrast with the “participant” matter. The high-precision velocity measurement of fully identified (charge and mass) spectator fragments –as is achievable with the FRS spectrometer in GSI Darmstadt- carries information on the properties of nuclear matter. Indeed, the slowing down of the fragments with decreasing mass may be linked with the in-medium nucleon-nucleon cross-section. Furthermore, the comprehension of the observed kinematical dispersion leads to the characterization of the various processes of fragment formation (multifragmentation, evaporation of intermediate-mass fragments). The combination of such information with the production cross-sections allows an evaluation of the dependence of these processes with the impact parameter (making the comparison with theoretical predictions easier). An analytical formula for the standard deviation of longitudinal momentum is developed; its universality and its predictive power make it a good tool for practical evaluations<br>Les collisions d’ions lourds aux énergies relativistes permettent de faire atteindre à la matière nucléaire des conditions extrêmes en température et en densité. La géométrie des collisions permet de définir la matière « spectatrice » (constituée de rémanents des projectiles initiaux) par opposition à la matière « participante ». La mesure de la vitesse des fragments spectateurs (identifiés en masse et en charge) avec une très grande précision, telle qu’accessible auprès du spectromètre FRS du laboratoire GSI de Darmstadt, renseigne sur les propriétés de la matière nucléaire. Ainsi, le freinage progressif des fragments avec la perte de masse engendrée dans la collision pourrait être lié à la section efficace nucléon-nucléon dans le milieu. D’autre part, la compréhension de la dispersion cinématique observée conduit à la caractérisation des divers processus de formation des fragments (multifragmentation, évaporation de fragments de masses intermédiaires). La combinaison de ces informations avec les sections efficaces de production permet une évaluation du lien entre ces processus et le paramètre d’impact (facilitant la comparaison aux prédictions théoriques). Une formule analytique pour la déviation standard de l’impulsion longitudinale est développée ; son universalité et sa prédictivité en font un bon outil pour des estimations pratiques

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45

Bacquias, Antoine Rami Fouad Schmidt Karl-Heinz. "Kinematical properties of spectator fragments in heavy-ion collisions at relativistic energies." Strasbourg : Université de Strasbourg, 2009. http://eprints-scd-ulp.u-strasbg.fr:8080/1047/01/BACQUIAS_Antoine_2008.pdf.

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46

Torrieri, Giorgio. "Statistical hadronization phenomenology in heavy ion collisions at SPS and RHIC energies." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280537.

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This dissertation examines the phenomenology of statistical hadronization at ultrarelativistic energies. We start with an overview of current experimental and theoretical issues in Relativistic heavy ion physics. We then introduce statistical hadronization, and show how it gives a description of particle abundances and spectra through relativistic covariance and entropy maximization. We argue that several statistical hadronization models are possible; In particular, a distinction can be made between equilibrated staged freeze-out in which post-formation hadron interactions play an important role in determining final-state observables, and non-equilibrium sudden freeze-out where spectra and abundances get determined at the same time and further interactions are negligible. We attempt to falsify sudden freeze-out by examining whether particle abundances and spectra can be described using the same formation temperature. This is done both in the chemical equilibrium framework, and using a chemical non-equilibrium ansatz. Our fits to experimental data suggest that the sudden freeze-out model explains both the particle abundances and spectra. We then try to extract the particle formation temperature, and quantify post-freeze-out hadronic interactions using experimentally observable resonances. We discuss observed resonances and suggest further measurements that have the potential to distinguish between the possible freeze-out scenarios experimentally. Finally, we infer from experimental data how particle formation proceeds in spacetime, in particular whether freeze-out dynamics agrees with the sudden freeze-out expectation. We examine particle spectra, and show that they are not sensitive enough to pick the right freeze-out dynamics. We suggest resonances and azimuthal anisotropy as experimental probes for this task.

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47

Rizzo, Carmelo. "Symmetry Energy Effects in Low Energy Heavy Ion Collisions with Exotic Beams." Thesis, Università degli Studi di Catania, 2011. http://hdl.handle.net/10761/124.

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We investigate the reaction path followed by Heavy Ion Collisions with exotic nuclear beams at low energies. The evolution of the system is described by a Stochastic Mean Field transport equation (SMF), where two parameterizations for the density dependence of symmetry energy (Asysoft and Asystiff) are implemented, allowing one to explore the sensitivity of the results to this ingredient of the nuclear interaction. We report the properties of the prompt dipole radiation, produced via a collective bremsstrahlung mechanism, in fusion reactions with exotic beams. We show that the gamma yield is sensitive to the density dependence of the symmetry energy below/around saturation. Moreover we find that the angular distribution of the emitted photons from such fast collective mode can represent a sensitive probe of its excitation mechanism and of fusion dynamics in the entrance channel. We will focus on the interplay between reaction mechanisms, fusion vs. break-up, that in exotic systems is expected to be influenced by the symmetry energy term at densities around the normal value. The new method described here, based on the event by event evolution of phase space Quadrupole collective modes will nicely allow to extract the fusion probability at relatively early times, when the transport results are reliable. Fusion probabilities for reactions induced by 132Sn on 64,58Ni targets at 10 AMeV are evaluated. We obtain larger fusion cross sections for the more n-rich composite system, and, for a given reaction, in the Asysoft choice. A collective charge equilibration mechanism (the Dynamical Dipole) is revealed in both fusion and break-up events, depending on the stiffness of the symmetry term just below saturation. Finally we investigate the effect of the mass asymmetry in the entrance channel for systems with the same overall isospin content and similar initial charge asymmetry. As expected we find reduced fusion probabilities for the more mass symmetric case, while the DDR strength appears not much affected. This is a nice confirmation of the prompt nature of such collective isovector mode.

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48

Gan, Hin Hark. "Nuclear dynamics in the mean field Vlasov equation." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65536.

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49

Kämpfer, Burkhard, M. W. Beinker, and G. Soff. "Estimates of Production Rates of SUSY Particles in Ultra-Relativistic Heavy-Ion Collisions." Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-30817.

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50

Peshier, André, G. Soff, O. P. Pavlenko, M. Hentschel, and Burkhard Kämpfer. "Thermal Open Charm Signals Versus Hard Initial Yields in ultrarelativistic Heavy-Ion Collisions." Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-31073.

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Exploiting a unique set of parton distribution functions we estimate hard processes for open charm, dilepton and mini-jet production. Assuming rapid thermalization within the mini-jet plasma we follow the evolution (expansion and chemical equilibration) of the parton matter and calculate the energy loss of charm quarks in this environment. A substantial part of charm is espected to thermalize. We try to estimate the thermalized open charm component in the final hadron spectra.

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