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Measurement of charmed hadron production in e±p deep inelastic scattering with the ZEUS detectorAllfrey, Philip Daniel January 2007 (has links)
Charmed hadron production has been studied in 225 pb<sup>-1</sup> of data collected with the ZEUS detector in the HERA-II runnning period. Studies were made in the D* → D<sup>0</sup>π → Kππ decay channel to determine the potential for the microvertex detector to improve charm signals. Integrated cross sections were measured for the decays D<sup>0</sup> → K<sup>0</sup><sub>s</sub>π⁺ π⁻, D<sup>±</sup> → K<sup>0</sup><sub>s</sub> π<sup>±</sup>, D<sup>±</sup>_s → K<sup>0</sup>s K<sup>±</sup> and Lambda<sup>±</sup>_c → Lambda<sup>0</sup>π<sup>±</sup> in the kinematic region 5< Q² < 1000 GeV², 0.02 < y < 0.7, 1.5 < pT(D,Lambda_c) < 20.0 GeV, -1.6 < pseudorapidity(D, Lambda_c) < 1.6. The D<sup>0</sup> cross section was additionally measured down to pT(D<sup>0</sup>) > 1.0 GeV. Differential cross sections as a function of Q², x, pT(D) and pseudorapidity(D) were measured for the D<sup>0</sup>, D<sup>±</sup>, and D_s<sup>±</sup> channels. The measurements were compared to next-to-leading order (NLO) QCD calculations, and good agreement found for all variables in all channels over the measured kinematic region. The strangeness-suppression factor, gamma_s = D_s<sup>±</sup>/(D<sup>±</sup> + D<sup>0</sup>), was measured and found to be in good agreement with values previously measured at HERA and elsewhere, and with the DJANGOH and RAPGAP Monte Carlo. The ratio of charmed baryons to mesons, Lambda_c<sup>±</sup>/(D<sup>±</sup> + D<sup>0</sup>), was measured and also found to be in good agreement with Monte Carlo.
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Zkoumání produkce podivných částic v jetech v experimentu ALICE na urychlovači LHC / Study of strange particle production in jets with the ALICE experiment at the LHCKučera, Vít January 2016 (has links)
Title: Study of strange particle production in jets with the ALICE experiment at the LHC Author: Vít Kučera Institute: Institute of Particle and Nuclear Physics Supervisors: RNDr. Jana Bielčíková, Ph.D., Nuclear Physics Institute of the CAS; Dr. Christian Kuhn, Institut Pluridisciplinaire Hubert CURIEN Abstract: Quark-gluon plasma is a state of matter existing under extreme energy densities and temperatures where quarks and gluons are deconfined. Complex phenomena occurring in the plasma emerge from the strong interaction of its constituents. This hot and dense strongly interacting matter can be created in ultra-relativistic heavy-ion collisions and its properties can be studied by measuring particles produced in the collisions. Partons produced in hard scatterings interact with the medium which modifies the production of particles in jets. Measurements of spectra of identified particles produced in jets represent an important tool for understanding the interplay of various hadronization mechanisms which contribute to the particle production in the medium created in heavy-ion collisions. In this thesis, we present the measurement of the pT spectra of Λ baryons and K0 S mesons produced in charged jets in central Pb-Pb collisions at the energy √ sNN = 2.76 TeV, measured in the ALICE experiment at the LHC. The...
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Study of strange particule production in jets with the alice experiment at the LHC / Étude de la production des particules étranges dans des jets avec l'expérience ALICE auprès du LHCKucera, Vit 15 November 2016 (has links)
Le plasma de quarks et de gluons est un état de matière obtenu lors de températures et de densités d’énergie extrêmes où les quarks et les gluons sont libres. Cette matière chaude et dense peut être créée dans les collisions d’ions lourds ultra-relativistes. Les mesures des spectres des particules identifiées produites dans des jets représentent un outil majeur permettant d'étudier les propriétés du plasma créé dans les collisions et d'ainsi comprendre les relations entre divers mécanismes contribuant à la production de particules dans ce milieu. Cette thèse présente une analyse des spectres en impulsion transverse des baryons Λ et mésons K0S produits dans des jets chargés lors de collisions Pb–Pb centrales à l'énergie sqrt(sNN) = 2.76 TeV mesurées avec ALICE au LHC. Les résultats sont utilisés pour discuter l'origine de l'augmentation du rapport entre baryons et mésons observée pour la production inclusive des particules dans les collisions d’ions lourds ultra-relativistes. / Quark–gluon plasma is a state of matter existing under extreme energy densities and temperatures where quarks and gluons are deconfined. This hot and dense strongly interacting matter can be created in ultra-relativistic heavy-ion collisions. Measurements of spectra of identified particles produced in jets represent a major tool for studying properties of the plasma created in the collisions and for understanding the interplay of various mechanisms which contribute to the particle production in this medium. In this thesis, we present the measurement of the transverse-momentum spectra of Λ baryons and K0S mesons produced in charged jets in central Pb–Pb collisions at the centre-of-mass energy sqrt(sNN) = 2.76 TeV, measured with ALICE at the LHC. The results of the analysis are used to discuss the origin of the enhancement of the baryon-to-meson ratio observed for the inclusive production of light-flavour particles in ultra-relativistic heavy-ion collisions.
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KOs and lambda production associated to high-p T charged hadrons in Pb-Pb collisions at √sNN = 2.76 TeV with ALICE : comparison between the hard and "soft" processes related to the production of hadrons / Production de mésons K0 S et de baryons lambda associés à des hadrons chargés de haut pT dans les collisions Pb-Pb du LHC à √sNN = 2.76 TeV avec l'expérience ALICE : comparaison entre les processus durs et "soft" liés à la production de hadronsSanchez Castro, Xitzel 31 March 2015 (has links)
Dans les collisions d'ions lourds ultra-relativistes (A-A), la matière se trouve dans des conditions extrêmes de densité d'énergie; elle forme un plasma de quarks et de gluons déconfinés. Aux énergies du RHIC et du LHC, le rapport baryon sur méson, tel Λ/K0S, prend des valeurs élevées sur une plage d'impulsions transverses intermédiaires pour les collisions centrales A-A. L'objectif de ce travail est de vérifier si la production accrue de baryons est seulement due à des effets collectifs au cœur du système formé ou s'il existe aussi un impact lié à une fragmentation des partons modifiée par le milieu. À l'aide de corrélations angulaires à deux hadrons, les K0S et Λ produits en association avec un hadron de haut pT (processus durs) sont séparés de ceux issus du milieu thermalisé (processus softs). Les rapports Λ/K0S à relier aux mécanismes durs et softs sont établis; les résultats sont obtenus pour les collisions Pb-Pb à √sNN = 2.76 TeV enregistrées en 2011 avec l'expérience ALICE. / In ultrarelativistic heavy-ion collisions, the QCD matter is under extreme conditions of energy density, forming a quark-gluon plasma (QGP), in which quarks and gluons are deconfined. At RHIC and LHC energies, a large baryon-to-meson ratio, like Λ/K0S, was observed within the transverse momentum range 2 < pT < 6 GeV/c for central heavy-ion collisions. The goal of this dissertation is to verify if the baryon-to-meson enhancement is only due to collective effects of the bulk of matter, and if there is also a contribution related to in-medium modifications of parton fragmentation.With two-hadron angular correlations, the K0S and Λ produced in association to an energetic hadron (hard processes) are separated from those originated from the thermalised medium (soft processes). The differential Λ/K0S ratios related to the soft or hard production processes are extracted. The results are obtained for the Pb-Pb collisions at √sNN = 2.76 TeV recorded in 2011 with the ALICE experiment.
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