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[{"key": "dc.contributor.advisor", "value": "Eskola, Kari J.", "language": null, "element": "contributor", "qualifier": "advisor", "schema": "dc"}, {"key": "dc.contributor.advisor", "value": "Niemi, Harri", "language": null, "element": "contributor", "qualifier": "advisor", "schema": "dc"}, {"key": "dc.contributor.author", "value": "Kukkonen, Kosmo", "language": null, "element": "contributor", "qualifier": "author", "schema": "dc"}, {"key": "dc.date.accessioned", "value": "2025-06-06T06:39:15Z", "language": null, "element": "date", "qualifier": "accessioned", "schema": "dc"}, {"key": "dc.date.available", "value": "2025-06-06T06:39:15Z", "language": null, "element": "date", "qualifier": "available", "schema": "dc"}, {"key": "dc.date.issued", "value": "2025", "language": null, "element": "date", "qualifier": "issued", "schema": "dc"}, {"key": "dc.identifier.uri", "value": "https://jyx.jyu.fi/handle/123456789/103140", "language": null, "element": "identifier", "qualifier": "uri", "schema": "dc"}, {"key": "dc.description.abstract", "value": "Monet ultrarelativistisissa raskasionit\u00f6rm\u00e4yksiss\u00e4 tuotetun kvarkki-gluoniplasman\ntasapainoa edelt\u00e4v\u00e4n tilan mallit perustuvat partonikaskadisimulaatioon. K\u00e4yt\u00e4mme\nt\u00e4llaista mallinnusta kuvaamaan massattomista kvarkeista ja gluoneista koostuvaa\nkaasua, joka on tilavuudeltaan \u00e4\u00e4ret\u00f6n, homogeeninen sek\u00e4 yhten\u00e4isess\u00e4 vakiol\u00e4mp\u00f6tilassa. T\u00e4ss\u00e4 ty\u00f6ss\u00e4 olemme kehitt\u00e4neet kineettisen kaskadisimulaation k\u00e4ytt\u00e4en geometrist\u00e4 t\u00f6rm\u00e4yskriteeri\u00e4 ja todenneet sen olevan tarkka alueessa n\u03c3^3/2 < 1, miss\u00e4 n on hiukkastiheys ja \u03c3 interaktion vaikutusala. T\u00e4t\u00e4 testattiin vertaamalla simulaation tuottamaa t\u00f6rm\u00e4ystaajuutta teoreettiseen arvoon.\nPartonisironnoille k\u00e4yt\u00e4mme johtavan kertaluvun kvanttiv\u00e4ridynamiikan h\u00e4iri\u00f6-\nteorian vaikutusaloja, joissa propagaattoreita on varjostettu Debye-massalla pienten ja suurten sirontakulmien singulariteettien est\u00e4miseksi. K\u00e4yt\u00e4mme my\u00f6s yhden efektiivisen aliprosessin (SES) approksimaatiota tutkimaan gg \u2192 gg -prosessin pienill\u00e4 t\u00f6rm\u00e4ysenergian \u221as arvoilla esiintyv\u00e4n divergenssin vaikutusta.\nTutkimme simulaatiollamme kaukana tasapainotilasta olevien systeemien isotro-\npisaatiota ja termalisaatiota tutkimalla leikkausj\u00e4nnitystensoria sek\u00e4 vertaamalla\nliikem\u00e4\u00e4r\u00e4jakaumaa Boltzmannin jakaumaan. Alkutila, jossa joka hiukkasella on sa-\nmansuuruinen liikem\u00e4\u00e4r\u00e4 xy-tasossa, isotropisoituu aikav\u00e4lill\u00e4 0.5 fm < t < 1.0 fm ja\ntermalisoituu v\u00e4lill\u00e4 2.4 fm < t < 3.5 fm systeemin l\u00e4mp\u00f6tilasta riippuen. Huomasimme, ett\u00e4 varjostusmassan muuttamisella ja odotetuilla alinta seuraavan kertaluvun korjauksilla on suuri vaikutus tasapainotilan saavuttamiseen. SES-approksimaatiota k\u00e4ytt\u00e4m\u00e4ll\u00e4 huomasimme, ettei pienen s:n t\u00f6rm\u00e4yksill\u00e4 ole huomattavaa vaikutusta isotropisaatioon eik\u00e4 termalisaatioon.", "language": "fi", "element": "description", "qualifier": "abstract", "schema": "dc"}, {"key": "dc.description.abstract", "value": "Many models for pre-equilibrium evolution of the quark-gluon plasma in ultrarelativistic heavy ion collisions are based on a parton cascade framework. We use such\na framework to simulate a gas consisting of massless quarks and gluons which is\ninfinite in volume, homogeneous and at a constant and uniform temperature. In this\nthesis, we have developed a kinetic cascade simulation using a geometric collision\ncriterion and tested it to be accurate in the region n\u03c3^3/2 < 1, where n is the particle density and \u03c3 the interaction cross section. This test was done by comparing the collision rate produced by our simulation to the one calculated from theory.\nFor the partonic scatterings, we use leading order perturbative quantum chromo-\ndynamical cross sections with the propagators screened using the Debye screening\nmass to control singularities in small and large scattering angles. We also use the\nsingle effective subprocess (SES) approximation to study the effects of the divergence of the gg \u2192 gg process cross section at low collision energies \u221as.\nUsing our simulation, we studied the thermalization and isotropization of systems\nwith far-from-equilibrium initial conditions by examining the anisotropic stress tensor and comparing the momentum distribution to the Boltzmann distribution. With initial conditions of each particle having the same energy and moving in the xy-plane, we found the system to isotropize in a time of 0.5 fm < t < 1.0 fm and to thermalize in 2.4 fm < t < 3.5 fm depending on the temperature of the system. We found that the screening mass and the expected next-to-leading order corrections have a large effect on reaching equilibrium. Using the SES approximation, we verified that small-s collisions do not significantly contribute to isotropization or thermalization.", "language": "en", "element": "description", "qualifier": "abstract", "schema": "dc"}, {"key": "dc.description.provenance", "value": "Submitted by Paivi Vuorio (paelvuor@jyu.fi) on 2025-06-06T06:39:15Z\nNo. of bitstreams: 0", "language": "en", "element": "description", "qualifier": "provenance", "schema": "dc"}, {"key": "dc.description.provenance", "value": "Made available in DSpace on 2025-06-06T06:39:15Z (GMT). No. of bitstreams: 0\n Previous issue date: 2025", "language": "en", "element": "description", "qualifier": "provenance", "schema": "dc"}, {"key": "dc.format.extent", "value": "90", "language": null, "element": "format", "qualifier": "extent", "schema": "dc"}, {"key": "dc.language.iso", "value": "eng", "language": null, "element": "language", "qualifier": "iso", "schema": "dc"}, {"key": "dc.rights", "value": "In Copyright", "language": null, "element": "rights", "qualifier": null, "schema": "dc"}, {"key": "dc.subject.other", "value": "parton cascade", "language": null, "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "thermalization", "language": null, "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "isotropization", "language": null, "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "Debye screening mass", "language": null, "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "collision rate", "language": null, "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.title", "value": "A kinetic simulation of a quark-gluon gas", "language": null, "element": "title", "qualifier": null, "schema": "dc"}, {"key": "dc.type", "value": "master thesis", "language": null, "element": "type", "qualifier": null, "schema": "dc"}, {"key": "dc.identifier.urn", "value": "URN:NBN:fi:jyu-202506064946", "language": null, "element": "identifier", "qualifier": "urn", "schema": "dc"}, {"key": "dc.contributor.faculty", "value": "Matemaattis-luonnontieteellinen tiedekunta", "language": "fi", "element": "contributor", "qualifier": "faculty", "schema": "dc"}, {"key": "dc.contributor.faculty", "value": "Faculty of Sciences", "language": "en", "element": "contributor", "qualifier": "faculty", "schema": "dc"}, {"key": "dc.contributor.department", "value": "Fysiikan laitos", "language": "fi", "element": "contributor", "qualifier": "department", "schema": "dc"}, {"key": "dc.contributor.department", "value": "Department of Physics", "language": "en", "element": "contributor", "qualifier": "department", "schema": "dc"}, {"key": "dc.contributor.organization", "value": "Jyv\u00e4skyl\u00e4n yliopisto", "language": null, "element": "contributor", "qualifier": "organization", "schema": "dc"}, {"key": "dc.contributor.organization", "value": "University of Jyv\u00e4skyl\u00e4", "language": null, "element": "contributor", "qualifier": "organization", "schema": "dc"}, {"key": "dc.subject.discipline", "value": "Teoreettinen fysiikka", "language": "fi", "element": "subject", "qualifier": "discipline", "schema": "dc"}, {"key": "dc.subject.discipline", "value": "Theoretical Physics", "language": "en", "element": "subject", "qualifier": "discipline", "schema": "dc"}, {"key": "dc.type.coar", "value": "http://purl.org/coar/resource_type/c_bdcc", "language": null, "element": "type", "qualifier": "coar", "schema": "dc"}, {"key": "dc.rights.copyright", "value": "\u00a9 The Author(s)", "language": "fi", "element": "rights", "qualifier": "copyright", "schema": "dc"}, {"key": "dc.rights.accesslevel", "value": "openAccess", "language": null, "element": "rights", "qualifier": "accesslevel", "schema": "dc"}, {"key": "dc.type.publication", "value": "masterThesis", "language": null, "element": "type", "qualifier": "publication", "schema": "dc"}, {"key": "dc.subject.yso", "value": "simulointi", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "fysiikka", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "t\u00f6rm\u00e4ykset", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "hiukkasfysiikka", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "kvarkki-gluoniplasma", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.rights.url", "value": "https://rightsstatements.org/page/InC/1.0/", "language": null, "element": "rights", "qualifier": "url", "schema": "dc"}]
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