The main purpose of Relativistic Heavy Ion Collider (RHIC) program is to study the Quark-Gluon Plasma (QGP), a deconfined state of matter believed to be created in ultra-relativistic heavy ion collisions. Heavy quarks, expected to be produced during the earlier stages of heavy ion collisions, serve as an important probe of the QGP.‎ ‎The following dissertation presents measurements of single muons resulting from the semileptonic decay of heavy flavor quarks in the rapidity range of $1.4 < vertetavert < 1.9$ for Cu+Cu nuclei collisions at $sqrt{s_{NN}}=200$ GeV measured by the PHENIX experiment. Single muon spectra were measured for three different centrality classes (0 - 20 \% , 20 - 40 \%, 40 - 94 \%) within the $p_{T}$ range of 1.0 - 4.0 GeV/c.‎ ‎To calculate single muon spectra, a full background estimate was statistically subtracted from inclusive spectra of muon candidate tracks reconstructed in the PHENIX muon arms. The background was predicted and estimated with a ``Hadron Cocktail", a full-scale data-driven Monte Carlo simulation. The hadron cocktail approach was originally developed and implemented to measure single muon production for Run-5 p+p collisions. First, the relevant light hadrons are generated with a ``realistic'' input (ratios of different particle species and $p_{T}$ spectra). The generated tracks are then propagated through the PHENIX detector geometry using GEANT. At the last step, introduced and implemented specifically for this analysis, the simulated tracks were embedded into real events and finally reconstructed with the PHENIX muon arms reconstruction software. This was done to realistically reproduce detector performance due to effects caused by colliding heavy ions. The hadron cocktail method provides a much better alternative to the previously attempted purely data-driven peacemeal approaches which suffer from very large systematic uncertainties.‎ ‎Finally, using baseline single muon measurements for p+p collisions, nuclear modification factors for all of the above specified centralities have been measured. These are the first measurements of single muon spectra and nuclear modification factors at forward angles for any two heavy colliding ion systems.

Lepton pairs resulting from the decay of heavy flavor mesons are an important tool to probe the hot and dense matter created in nucleus-nucleus collisions at the Relativistic Heavy Ion Collider. Due to their large mass, heavy quarks are produced in the earliest stages of the collision and will, therefore, experience the full evolution of the system. The yield of heavy flavor mesons can be measured through their semi-leptonic decay channel by constructing like-sign and unlike-sign lepton pairs. Cross section measurements in p + p collisions provide a test of perturbative quantum chromodynamics (pQCD) theory in addition to a crucial baseline measurement to study the hot and cold nuclear matter effects present in heavy ion collisions. For the first time, the b¯b cross section in p+p collisions at √s = 500 GeV is measured. The results are based on the yield of high mass, like-sign dimuons measured in the PHENIX muon arm acceptance (1.2 < |y| < 2.2). The extrapolated total cross section is 25.2 ± 3.2 (stat) +11.4 -9.5 µb (sys). The cross section is comparable to pQCD calculation within uncertainties.

A measurement of J/\Psi polarization has been performed for 200 GeV proton+proton collisions with the PHENIX Muon Arms at RHIC. The results from the current data show no polarization within the PHENIX acceptance range. The results are consistent with the current model predictions and other experimental measurements.

Lepton pairs resulting from the decay of heavy flavor mesons are an important tool to probe the hot and dense matter created in nucleus-nucleus collisions at the Relativistic Heavy Ion Collider. Due to their large mass, heavy quarks are produced in the earliest stages of the collision and will, therefore, experience the full evolution of the system. The yield of heavy flavor mesons can be measured through their semi-leptonic decay channel by constructing like-sign and unlike-sign lepton pairs. Cross section measurements in p + p collisions provide a test of perturbative quantum chromodynamics (pQCD) theory in addition to a crucial baseline measurement to study the hot and cold nuclear matter effects present in heavy ion collisions. For the first time, the b¯b cross section in p+p collisions at √s = 500 GeV is measured. The results are based on the yield of high mass, like-sign dimuons measured in the PHENIX muon arm acceptance (1.2 < |y| < 2.2). The extrapolated total cross section is 25.2 ± 3.2 (stat) +11.4 -9.5 µb (sys). The cross section is comparable to pQCD calculation within uncertainties.

Germanium detectors are used by the scientic community to study cosmic X-ray sources. In order to localize the exact 3D position of an X-ray interaction, double-sided strip detectors are used. Each strip requires a single readout electronic stage to convert induced charge into a voltage pulse. We present here the computer simulation of such an analog electronic stage. Each particular element of this stage, i.e. charge-sensitive preamplier, amplier, oset corrector, lter and analog-to-digital converter, will be simulated in detail, taking into account temperature and noise performances. Furthermore, a tool to simultaneously simulate multiple strips for several X-ray interaction points was developed. This tool will facilitate the study of all electronic chains as a whole. / <p>Validerat; 20120908 (anonymous)</p>

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Les collisions d'ions lourds ultra-relativistes représentent le seul moyen pour appréhender en laboratoire le diagramme de phase de la QCD, la théorie de l'interaction forte. Les prédictions théoriques les plus récentes, obtenues par la technique de calcul sur réseau, prévoient une transition de phase entre la matière nucléaire froide (un gaz hadronique) et un plasma de quarks et de gluons (milieu déconfiné). Parmi les différentes sondes expérimentales possibles, l'intérêt des saveurs lourdes est en principe de pouvoir caractériser le milieu produit lors d'une collision entre ions lourds, mais également de pouvoir obtenir des informations sur son évolution spatio-temporelle. Leur étude peut se faire entre autres par le biais de leur canal de désintégration en muons. Cette Habilitation à Diriger des s développe dans une première partie la problématique des collisions d'ions lourds ultra-relativistes, en mettant l'accent sur l'étude des saveurs lourdes. Dans une deuxième partie, les résultats obtenus auprès du collisionneur RHIC (BNL, New York) sont passés en revus, et l'analyse du spectre en masse des dimuons menée au sein de l'expérience PHENIX est détaillée. Enfin, la troisième partie décrit d'une part les développements instrumentaux réalisés pour le système de déclenchement des muons dans l'expérience ALICE auprès du LHC (CERN, Genève), et d'autre part les performances attendues pour l'étude des dimuons.