Dissertations / Theses on the topic 'Quark spin'
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Dharmaratna, Welathantri G. D. "Massive quark polarization in Quantum Chromodynamics subprocesses /." Thesis, Connect to Dissertations & Theses @ Tufts University, 1990.
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Thesis (Ph.D.)--Tufts University, 1990.Adviser: Gary R. Goldstein. Submitted to the Dept. of Physics. Includes bibliographical references. Access restricted to members of the Tufts University community. Also available via the World Wide Web;
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Schmitt, Andreas. "Spin-one color superconductivity in cold and dense quark matter." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=974955094.
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McLaughlan, Thomas. "Measurement of spin correlation in top quark pair production at ATLAS." Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/4826/.
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This thesis presents a study of spin correlation in ttˉ production in the ATLAS detector, in proton-proton collisions, corresponding to an integrated luminosity of 4:7fb\(^1\), with a centre of mass energy of \(\surd\)s = 7 TeV. Both the dilepton and single lepton channels are considered, the latter providing a greater challenge due to the necessity to reconstruct the down-type quark resulting from the W boson decay. A simple technique is employed to reconstruct single lepton ttˉ events, with the transverse angle between the charged lepton and down-type quark used as a probe of the spin correlation. In the dilepton channel, the transverse angle between both charged leptons is used. The extracted value of spin correlation in each channel is consistent with Standard Model predictions, with the result in the e\(\mu\) channel alone sufficient to exclude a model without spin correlation at 7:8\(\sigma\). Also described is the author's contribution to the maintenance and development of the Atlantis Event Display.
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Head, Timothy. "Top quark spin correlations and leptonic forward-backward asymmetries at D0." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/top-quark-spin-correlations-and-leptonic-forwardbackward-asymmetries-at-d0(a07247a9-4eac-4bc4-8c1f-48c9316e90aa).html.
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The top quark is the heaviest fundamental particle. Its correspondingly short lifetime implies that it will decay before top flavoured hadrons can form. This provides an opportunity to study the properties of a quark without the effects of hadronisation, which is unique in the standard model.Using data recorded by the D0 experiment at the Fermilab Tevatron collider, and corresponding to \unit[5.4]{fb^{-1}} of proton-antiproton collisions two analyses of the production and decay mechanism of top quarks are presented in this thesis. In the standard model the directions of the spin of top quarks produced in pairs by the strong interaction are expected to be correlated. In the first analysis, the strength of the correlation is extracted from the angles of the two leptons in the top quark and antiquark rest frames, yielding a correlation strength C=0.10\pm0.45. This is in agreement with the NLO QCD prediction within two standard deviations, but also in agreement with the no correlation hypothesis.In the second analysis, forward-backward asymmetries in top quark-antiquark production are measured using the charged leptons from top quark decays. We find that the angular distributions of \ell^{\mathrm{-}} relative to antiprotons and \ell^{+} relative to protons are in agreement with each other. Combining the two distributions and correcting for detector acceptance we obtain the forward-backward asymmetry \al=\left(5.8\pm5.1\mathrm{(stat)}\pm1.3\mathrm{(syst)}\right)\%, compared to the standard model prediction of \al\mathrm{(predicted)}=\left(4.7\pm0.1\right)\%.
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Head, Simon James. "Spin correlation in the dileptonic decay of top quark pairs at ATLAS." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.506635.
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Tallini, Hugh Arthur McLaren. "A measurement of the quark spin distributions of the nucleon at HERMES." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367159.
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Ronniger, Michael [Verfasser]. "Spin and Flavour dependent Interactions within a Quark Model for Baryons / Michael Ronniger." Bonn : Universitäts- und Landesbibliothek Bonn, 2013. http://d-nb.info/104497110X/34.
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Debastiani, Vinícius Rodrigues. "Espectroscopia do Todo-Charme Tetraquark." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-08072016-001417/.
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Introduzimos um método não-relativístico para estudar a espectroscopia de estados ligados hadrônicos compostos por quatro quarks charme, na figura de diquark-antidiquark. Resolvendo numericamente a equação de Schrödinger com dois potenciais diferentes inspirados no potencial de Cornell, de uma maneira semelhante aos modelos de quarkonium pesado para mésons, nós fatoramos o problema de 4 corpos em três sistemas de 2 corpos: primeiro o diquark e o antidiquark, que são compostos por dois quarks (antiquarks) em um estado de antitripleto de cor. No próximo passo eles são considerados como os blocos para construir o tetraquark, onde a sua interação leva a um singleto de cor. Termos dependentes de spin (spin-spin, spin-órbita e tensor) são usados para descrever o desdobramento do espectro e a separação entre estados com diferentes números quânticos. Atenção especial é dada à interação do tensor entre duas partículas de spin 1, com uma discussão detalhada da estratégia adotada. A interação spin-spin é tratada perturbativamente no primeiro modelo e incluída no potencial de ordem zero no segundo. A contribuição de cada termo de interação também é analisada e comparada. Dados experimentais recentes de estados bem estabelecidos de mésons de charmonium são utilizados para fixar os parâmetros de ambos os modelos (em um procedimento de ajuste minimizando chi quadrado), obtendo uma reprodução satisfatória do espectro do charmonium. As diferenças entre modelos são discutidas no contexto do charmonium, diquarks e tetraquarks. Nós concluímos que quase todas as ondas S e P (e as respectivas primeiras excitações radiais) do todo-charme tetraquark composto por diquarks de spin 1 estão entre 5.8 e 7 GeV, acima do limite de dissociação espontânea em pares de charmonium de baixa energia como dois eta_c ou J/psi, o que sugere que esses poderiam ser os canais ideais para procurar por esses estados, e desenvolver o atual conhecimento de estados multiquarks.We introduce a non-relativistic framework to study the spectroscopy of hadronic bound states composed of four charm quarks in the diquark-antidiquark picture. By numerically solving the Schrödinger equation with two different Cornell-inspired potentials in a similar way of heavy quarkonium models of mesons, we factorize the 4-body problem into three 2-body systems: first the diquark and the antidiquark, which are composed of 2 quarks (antiquarks) into a color antitriplet state. In the next step they are considered as the tetraquark building blocks, where their interaction leads to a color singlet. Spin-dependent terms (spin-spin, spin-orbit and tensor) are used to describe the splitting structure of the spectrum and account for different quantum numbers of each state. Special attention is given to the tensor interaction between two particles of spin 1, with a detailed discussion of the adopted strategy. The spin-spin interaction is addressed perturbatively in the first model and included in the zeroth-order potential in the second one. The contribution of each interaction term is also analysed and compared. Recent experimental data of reasonably well-established charmonium mesons are used to fix the parameters of both models (with a fitting procedure minimizing chi square), obtaining a satisfactory reproduction of charmonium spectrum. The differences between models are discussed in the charmonium, diquark and tetraquark context. We conclude that almost all the S and P waves (and respective first radial excitations), of the all-charm tetraquark composed by spin 1 diquarks are in the range between 5.8 to 7 GeV, above the threshold of spontaneous decay in low-lying charmonium pairs, like two eta_c or J/psi, what suggests that this could be the ideal channels to look for these states, and develop the current understanding of multiquark states.
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Ohlsson, Tommy. "Properties of baryons in the chiral quark model." Licentiate thesis, KTH, Fysik, 1997. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-756.
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In this thesis, several properties of baryons are studied using the chiral quark model. The chiral quark model is a theory which can be used to describe low energy phenomena of baryons. In Paper 1, the chiral quark model is studied using wave functions with configuration mixing. This study is motivated by the fact that the chiral quark model cannot otherwise break the Coleman–Glashow sum-rule for the magnetic moments of the octet baryons, which is xperimentally broken by about ten standard deviations. Configuration mixing with quark-diquark components is also able to reproduce the octet baryon magnetic moments very accurately. In Paper 2, the chiral quark model is used to calculate the decuplet baryon magnetic moments. The values for the magnetic moments of the ++and− are in good agreement with the experimental results. The total quark spin polarizations are also calculated and are found to be significantly smaller than the non-relativistic quark model results. In Paper 3, the weak form factors for semileptonic octet baryon decays are studied in the chiral quark model. The “weak magnetism” form factors are found to be consistent with the conserved vector current (CVC) results and the induced pseudotensor form factors, which seem to be model independent, are small. The results obtained are in general agreement with experiments and are also compared with other model calculations.QC 20100618
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Neep, Thomas James. "A measurement of spin correlation in top anti-top pairs and a search for top squarks at √s=8 TeV using the ATLAS detector." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/a-measurement-of-spin-correlation-in-top-antitop-pairs-and-a-search-for-top-squarks-at-sqrts8-tev-using-the-atlas-detector(cfb7f020-f0b5-4040-a17c-cde6dcc8d08d).html.
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The first measurement of the spin correlation strength in pairs of top quarks at √s=8 TeV is presented, using data collected using the ATLAS detector, corresponding to an integrated luminosity of 20.3 fb⁻¹. Dileptonically decaying tt^- events are selected with two high-pT leptons and at least two jets, one of which is required to be b-tagged. The azimuthal angle between the two charged leptons, Δφ, is used to measure the degree of spin correlation of top quark pairs. The extracted value of fSM, which is a measure of the spin-correlation strength, is fSM=1.20 ± 0.14. This is the most precise spin-correlation measurement to date. Using the Δφ distribution, a search for Supersymmetric top squarks is performed, with the assumption that the top squarks decay to a top quark and a neutralino. No excess of events is observed and top squarks with masses between the top quark mass and 191 GeV are excluded at 95% confidence level, extending previous limits.
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Flay, David. "Measurements of the Neutron Longitudinal Spin Asymmetry A1 and Flavor Decomposition in the Valence Quark Region." Diss., Temple University Libraries, 2014. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/286478.
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PhysicsPh.D.
The current data for the nucleon-virtual photon longitudinal spin asymmetry A1 on the proton and neutron have shown that the ratio of the polarized-to-unpolarized down-quark parton distribution functions, Δ d/d, tends towards -1/2 at large x, in disagreement with the perturbative QCD prediction that Δ d/d approaches 1 but more in line with constituent quark models. As a part of experiment E06-014 in Hall A of Jefferson Lab, double-spin asymmetries were measured in the scattering of a longitudinally polarized electron beam of energies 4.74 and 5.89 GeV from a longitudinally and transversely polarized 3He target in the deep inelastic scattering and resonance region, allowing for the extraction of the neutron asymmetry A1n and the ratios Δ d/d and Δ u/u. We will discuss our analysis of the data and present results for A1 and g1/F1 on both 3He and the neutron, and the resulting quark ratios for the up and down quarks in the kinematic range of 0.2 2 2 for our deep inelastic scattering data. Invoking duality, we also extract A1n and g1n/F1n in the resonance region, characterized by 0.6 2 2. Our measurements are compared to the world data and various theoretical models and more recent predictions using the Dyson-Schwinger Equation approach. We also present analysis of the unpolarized cross section data, which contributes to the g1 spin structure function and eventually the a2 matrix element, an x2-weighted moment of g1. The extracted a2 data are compared to a Lattice QCD calculation.
Temple University--Theses
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Howarth, James William. "Observation of spin correlations in tt̄ events at √s = 7 TeV using the ATLAS detector." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/observation-of-spin-correlations-in-ttbar-events-at-boldmathsqrts--7tev-using-the-atlas-detector(61844fe2-16c0-486e-9ceb-9e72425b7b20).html.
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This thesis presents measurements of the the spin correlation strength in top anti-top quark pair production at the LHC using the ATLAS detector. The data used corresponds to 4.6 fb−1 of integrated luminosity taken during 2011 at the LHC at a center of mass energy of 7 TeV. The spin correlation is studied utilising different observables with different sensitivities to the production mechanism, in particular to gluon-gluon fusion in the like or unlike helicity state, quark anti- quark annihilation in the unlike helicity state, or a combination of the three. In addition cuts are made on the invariant mass of the ttbar system to enhance or suppress contributions from different initial state production mechanisms. The analysis presented is a precision test of both ttbar production and decay in the SM. These measurements are compared to the most current theoretical predictions. No deviation from the SM expectation was observed. In a subset of the data, corresponding to an integrated luminosity of 2.1 fb−1, the hypothesis of zero spin correlation is excluded at 5.1 standard deviations.
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McAndrew, Michael Gabriel. "A measurement of the quark polarisation of the nucleon." Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366732.
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Mammei, Juliette Mae. "Parity-Violating Elastic Electron Nucleon Scattering: Measurement of the Strange Quark Content of the Nucleon and Towards a Measurement of the Weak Charge of the Proton." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/27661.
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The experiments discussed in this thesis exploit parity violation in elastic electron proton
scattering in order to measure properties of the nucleon. Both experiments make use of
the high quality, highly polarized electron beam available at Thomas Jefferson National
Accelerator Facility. Qweak will measure the weak mixing angle, sin2θW, via a measurement
of the weak charge of the proton, at a four-momentum transfer, Q2~0.026 GeV2/c2. The
precision of this measurement gives Qweak access to new physics at the scale of 2.3 TeV,
making it a test of the standard model. The G0 experimental program provides the fully
separated contributions of the strange quark to the charge and magnetization distributions of
the nucleon at two different values of four-momentum transfer, Q2 ~ 0.22 and 0.63 GeV2/c2. The measurement of the strange quark content of the proton in the G0 experimental program
and other parity-violating electron scattering experiments provides a measurement of the
hadronic contribution to the asymmetry in Qweak.
In addition, G0 was able to measure the parity-conserving beam normal single spin
asymmetries that provide a measurement of the imaginary part of two photon exchange.
The measurement of this asymmetry is necessary to understand the systematic contribution
to measurements of parity-violating asymmetries, but it is also an important physics result.
Recent theoretical work has shown that higher order radiative effects, such as two photon
exchange, may be able to explain discrepancies between experiments which measure the ratio
of the electric and magnetic form factors of the proton. The measurement of the transverse or
beam normal single spin asymmetries provides a benchmark for theories that estimate the size
of radiative corrections that are important for precision electroweak scattering experiments
such as those described in this thesis. The results of the measurement of the transverse
asymmetries at backward angles in G0 are presented at the two values of Q2 ~ 0.22 and 0.63 GeV2/c2 for hydrogen. Results for deuterium, which can provide the first measurements of the beam normal single spin asymmetries on the neutron, are also presented.Ph. D.
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Levy, Mark. "Inclusive and differential measurements of spin correlation in top-antitop quark pairs at √s = 8 TeV using the ATLAS detector." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6995/.
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A measurement of the spin correlation strength in top-antitop pairs is presented, using protonproton collision data collected at the ATLAS detector with a centre of mass energy of √s = 8 TeV and an integrated luminosity of 20.3 fb\(^{-1}\). An inclusive measurement is made, as well as a differential measurement as a function of the top-antitop invariant mass. Additionally, these measurements are made both at detector level and unfolded to a parton level distribution. Selected events are required to have exactly two oppositely charged leptons (either electrons or muons), a large missing transverse energy and at least two hadronic jets, at least one of which must be tagged as originating from a b-quark. The azimuthal separation between the two charged leptons, Δφ, is used to measure the degree of spin correlation. The measured distribution is compared to a Standard Model prediction and a model with no spin correlation. It is found that the results all favour the Standard Model prediction over the uncorrelated model, with the data found to be several standard deviations away from the uncorrelated scenario.
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Höhle, Felix [Verfasser], Achim [Akademischer Betreuer] Stahl, and Werner [Akademischer Betreuer] Bernreuther. "Measurement of spin correlation in dileptonic top quark pair decays with the CMS experiment / Felix Höhle ; Achim Stahl, Werner Bernreuther." Aachen : Universitätsbibliothek der RWTH Aachen, 2015. http://d-nb.info/1128731223/34.
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Höhle, Felix Verfasser], Achim [Akademischer Betreuer] [Stahl, and Werner [Akademischer Betreuer] Bernreuther. "Measurement of spin correlation in dileptonic top quark pair decays with the CMS experiment / Felix Höhle ; Achim Stahl, Werner Bernreuther." Aachen : Universitätsbibliothek der RWTH Aachen, 2015. http://d-nb.info/1128731223/34.
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Resende, B. "Étude du quark top avec ATLAS au LHC.Mise en route du calorimètre électromagnétique." Phd thesis, Université de la Méditerranée - Aix-Marseille II, 2007. http://tel.archives-ouvertes.fr/tel-00159908.
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En 2007 aura lieu au CERN le démarrage du collisionneur LHC qui étudiera l'origine de la masse et cherchera les signes d'une nouvelle physique. L'expérience ATLAS en exploitera les potentialités avec un détecteur généraliste multicouches.L'étude du quark top sera une étape importante : ses propriétés peuvent révéler une éventuelle nouvelle physique. Dans ce but, la polarisation du quark top et du boson W ont été étudiées avec une simulation détaillée du détecteur, dont les résultats confirment la simulation simplifiée. Ils indiquent une précision de 1 à 7 % avec 10 fb-1 de données, adéquate pour écarter ou retenir divers modèles de nouvelle physique.
Le calorimètre électromagnétique d'ATLAS est crucial pour l'observation des électrons et photons, et donc pour la recherche du boson de Higgs. Sa mise en route est illustrée ici par l'analyse des rampes reliant le calibrage au signal mesuré, ainsi qu'une analyse des muons cosmiques, premier test de la chaîne de lecture dans de vraies conditions de fonctionnement.
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Galler, Peter. "Effects of heavy Higgs bosons in the hadronic production of top-quark pairs including QCD corrections." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/18796.
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In dieser Disseratation wird eine mögliche Erweiterung des Standardmodells der
Elementarteilchen (SM) im Higgs-Sektor mithilfe von Topquarkpaarproduktion am
Large Hadron Collider untersucht. Insbesondere wird dabei auf das sogenannte
Zwei-Higgs-Duplettmodell eingegangen. Dieses Modell führt mehrere Spin-0
Bosonen (auch Higgsbosonen genannt) zusätzlich zum SM-Higgsboson ein. Dabei
wird in dieser Arbeit von der Annahme ausgegangen, dass diese zusätzlichen
Higgsbosonen schwer genug sind um in ein Top-Antitop-Paar zu zerfallen. Somit
können die experimentellen Signaturen dieser neuen Teilchen mit Hilfe von
Observablen der Topquarkpaarproduktion untersucht werden. Dazu wird die
resonante Erzeugung von schweren Higgsbosonen und deren Zerfall in
Topquarkpaare bis einschließlich Quantenkorrekturen in der nächst-zu-führenden
Ordnung (NLO) in der QCD-Kopplungskonstanten berechnet. Weiterhin wird die
volle Spininformation des Top-Antitop-Paares beibehalten, welche die Analyse
von spinabhängigen Observablen erlaubt. Diese können, insbesondere in Falle von
Top-Antitop-Spinkorrelationen, sehr sensitiv auf Effekte schwerer Higgsbosonen
sein. Dies zeigt sich besonders in Vergleich zu spinunabhängigen Observablen.
Die Sensitivität von spinabhängigen Observablen kann zudem noch durch
entsprechende Schnitte auf den Phasenraum von Top- und Antitopquark verstärkt
werden. In dieser Dissertation wird ein Verfahren vorgestellt, mit dessen Hilfe
sich die Spinkorrelationen identifizieren lassen, welche die größte
Sensitivität auf die Effekte schwerer Higgsbosonen aufweisen. Außerdem wird
durch die Berechnung der Beiträge zur NLO u.a. gezeigt, dass diese Beiträge
wichtig sind um aussagekräftige und robuste Observablen zu definieren. Die
Ergebnisse der NLO, die in dieser Arbeit vorgestellt werden, sind die ersten
ihrer Art für die resonante Erzeugung von schweren Higgsbosonen und deren
Zerfall in Topquarkpaare.In this dissertation a possible extension of the standard model of particle physics (SM) in the Higgs sector is investigated using top-quark pair production at the Large Hadron Collider as a probe. In particular, the so-called two-Higgs-doublet model (2HDM) is studied. The 2HDM introduces several spin-0 bosons (which are also called Higgs bosons) in addition to the SM Higgs boson. In this thesis these additional Higgs bosons are assumed to be heavy enough to decay into a top-antitop quark pair. Thus, the experimental signatures of these new particles can be studied through observables of top-quark pair production. To this end the resonant production of heavy neutral Higgs bosons and their decay into top-quark pairs in calculated up to next-to-leading order corrections in the QCD coupling constant retaining the full spin information of the top-antitop pair. This allows to analyse spin dependent observables which can be more sensitive to effects of heavy Higgs bosons than spin independent ones especially in the case of top-antitop spin correlations. The additional application of kinematical cuts on the phase space of top and antitop quarks can enhance the sensitivity further. In this thesis a method is presented that can be used to construct the spin correlation which is most sensitive to the effects of heavy Higgs bosons on top-quark pair production. Furthermore, it is shown that the next-to-leading order corrections are required to construct observables which entail robust predictions. The results for the next-to-leading order in the QCD coupling constant presented in this thesis were the first ones given for resonant heavy Higgs production and decay into top-quark pairs.
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Pequegnot, Anne-Laure. "Recherche de nouvelles particules de spin 0 se désintégrant en paires de quarks top-antitop et calibration en énergie des jets au-delà du TeV avec l’expérience CMS au LHC." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1165/document.
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L'expérience CMS auprès du LHC, grand collisionneur de hadrons, est un détecteur généraliste qui permet d'étudier tous les aspects des collisions proton-proton produites par le LHC : de l'étude du Modèle Standard et du boson de Higgs à la recherche de signaux de nouvelle physique au-delà du Modèle Standard.La première partie de cette thèse est dédiée à la calibration en énergie des jets dans CMS, un des plus grands défis et une étape fondamentale pour la réussite du programme de physique dans cet environnement hadronique. Plus particulièrement, l'étude des événements multijets permet de contraindre l'échelle en énergie des jets au-delà du TeV. Les corrections en énergie ainsi extraites sont primordiales pour les analyses de physique utilisant des jets, et sont utilisées par toute la collaboration CMS.La deuxième partie est consacrée à la recherche de particules de spin 0 se désintégrant en paires de quarks top-antitop. En effet, de nombreux modèles de nouvelle physique prédisent de nouvelles particules scalaires ou pseudoscalaires avec un fort couplage au quark top. Une étude phénoménologique de deux de ces modèles est présentée, à savoir les modèles à deux doublets de Higgs (2HDM) et l'extension supersymétrique minimale du Modèle Standard (MSSM). Ces modèles offrent tous deux un secteur de Higgs enrichi avec entre autre deux bosons de Higgs neutres additionnels, un scalaire et un pseudoscalaire. Une analyse du spectre de masse invariante des paires top-antitop utilisant les données collectées par CMS en 2012 à une énergie dans le centre de masse de 8 TeV visant à mettre en évidence l'existence de telles particules est menée. Cette analyse prend en compte pour la première fois les effets des interférences entre la production des paires top-antitop du Modèle Standard et la production résonante à travers la nouvelle particule de spin 0. Il est montré que l'impact des interférences ne peut être négligé. Aucune déviation par rapport aux prédictions théoriques du Modèle Standard n'a été observée dans le spectre de masse invariante des paires top-antitop. Un premier aperçu des données à 13 TeV est également présentéThe CMS experiment at the LHC, the Large Hadron Collider, is a general-purpose detector built to study the proton-proton collisions produced by the LHC, corresponding to a broad physics programme ranging from studying the Standard Model and the Higgs bosons to searching for signal of new physics beyond the Standard Model.The first part of this thesis is dedicated to the jet energy calibration in CMS, one of the most challenging and crucial steps for the sucess of the physics programme within the hadronic environment. More specifically, the study of multijet events allows to constraint the jet energy scale beyond the TeV-scale. The jet energy corrections thus obtained are fundamental for the physics analyses using jets, and are used by all the CMS collaboration.The second part of this manuscript is dedicated to the search for new spin 0 particles decaying into top-antitop quarks pairs. Indeed, several new physics models predict new scalar or pseudoscalar particles with an enhanced coupling to the top quark. A phenomenological study of two of those models is presented, namely the two higgs doublet models (2HDM) and the minimal supersymmetric extension of the Standard Model (MSSM). These models both offer an enriched Higgs sector with in particular two additional neutral Higgs bosons, one scalar and one pseudoscalar. The analysis of the top-antitop pairs mass spectrum using data collected by CMS in 2012 at an energy in the center of mass of 8 TeV is presented, looking for such particles. This search takes into account for the first time the effects of interference between Standard Model top-antitop pairs production and its resonant production through the spin 0 particle. This work shows the impact of interference cannot be neglected. No deviation from the Standard Model predictions has been observed in the top-antitop mass spectrum. A first look at 13 TeV data is also presented
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Ohlsson, Tommy. "Dynamics of quarks and leptons : theoretical Studies of Baryons and Neutrinos." Doctoral thesis, KTH, Fysik, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2991.
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The Standard Model of Elementary Particle Physics (SM) is the present theoryfor the elementary particles and their interactions and is a well-established theorywithin the physics community. The SM is a combination of Quantum Chromodynamics(QCD) and the Glashow{Weinberg{Salam (GWS) electroweak model. QCDis a theory for the strong force, whereas the GWS electroweak model is a theoryfor the weak and electromagnetic forces. This means that the SM describes allfundamental forces in Nature, except for the gravitational force. However, the SMis not a nal theory and some of its problems will be discussed in this thesis.In the rst part of this thesis, several properties of baryons are studied suchas spin structure, spin polarizations, magnetic moments, weak form factors, andnucleon quark sea isospin asymmetries, using the chiral quark model (QM). TheQM is an eective chiral eld theory developed to describe low energy phenomena of baryons, since perturbative QCD is not applicable at low energies. The resultsof the QM are in good agreement with experimental data.The second part of the thesis is devoted to the concept of quantum mechanicalneutrino oscillations. Neutrino oscillations can, however, not occur within the GWSelectroweak model. Thus, this model has to be extended in some way. All studiesincluding neutrino oscillation are done within three avor neutrino oscillationmodels. Both vacuum and matter neutrino oscillations are considered. Especially,global ts to all data of candidates for neutrino oscillations are presented and alsoan analytical formalism for matter enhanced three avor neutrino oscillations usingtime evolution operators is derived. Furthermore, investigations of matter eectswhen neutrinos traverse the Earth are included.The thesis begins with an introductory review of the QM and neutrino oscillationsand ends with the research results, which are given in the nine accompanyingscientic articles.QC 20100616
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Dutta, Chiranjib. "MEASUREMENT OF SINGLE-TARGET SPIN ASYMMETRIES IN THE ELECTROPRODUCTION OF NEGATIVE PIONS IN THE SEMI-INCLUSIVE DEEP INELASTIC REACTION n↑(e,éπ¯)X ON A TRANSVERSELY POLARIZED 3He TARGET." UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_diss/29.
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The experiment E06010 measured the target single spin asymmetry (SSA) in the semiinclusive deep inelastic (SIDIS) n↑(e,éπ¯)X reaction with a transversely polarized 3He target as an effective neutron target. This is the very first independent measurement of the neutron SSA, following the measurements at HERMES and COMPASS on the proton and the deuteron. The experiment acquired data in Hall A at Jefferson Laboratory with a continuous electron beam of energy 5.9 GeV, probing the valence quark region, with x = 0.13→0.41, at Q2 = 1.31→3.1 GeV2. The two contributing mechanisms to the measured asymmetry, viz, the Collins effect and the Sivers effect can be realized through the variation of the asymmetry as a function of the Collins and Sivers angles. The neutron Collins and Sivers moments, associated with the azimuthal angular modulations, are extracted from the measured asymmetry for the very first time and are presented in this thesis. The kinematics of this experiment is comparable to the HERMES proton measurement. However, the COMPASS measurements on deuteron and proton are in the low-x region. The results of this experiment are crucial as the first step toward the extraction of quark transversity and Sivers distribution functions in SIDIS. With the existing results on proton and deuteron, these new results on neutron will provide powerful constraints on the transversity and Sivers distributions of both the u and d-quarks in the valence region.
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Andrieux, Vincent. "Polarisation of quarks and gluons inside the nucleon." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112244/document.
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Cette thèse présente un travail relatif à l'étude de la structure en spin longitudinal du nucléon. Le but est de déterminer la contribution des constituants du proton, quarks et gluons, à la formation de son spin 1/2. L'analyse s'appuie sur les données de l'expérience COMPASS qui bénéficie d'un faisceau de muons polarisés à 200 GeV diffusé sur les protons polarisés d'une cible d'ammoniac (NH₃) de 1,2 m de long. On mesure l'asymétrie de spin longitudinal des sections efficaces de diffusion profondément inélastique. On extrait la fonction de structure en spin du proton, g₁p, étendant la couverture cinématique mondiale à des régions inexplorées jusqu'à maintenant (0,0036 < x < 0,57; 1,03 < Q² (GeV/c)² < 96 et 23 < W² (GeV/c)² < 320). Les résultats, d'une grande précision statistique, sont inclus dans une analyse des données mondiales de g₁p, g₁d et g₁n (proton, deutéron et neutron) au 2ème ordre de QCD afin de paramétrer les distributions de quarks et de gluons polarisés. L'étendue de la couverture cinématique en x et Q² des données mondiales de g₁, un élément déterminant pour la sensibilité à la polarisation des gluons ΔG, s'avère trop limitée pour constituer une extraction précise de celle-Ci. Néanmoins, l'analyse QCD permet de déterminer la contribution du spin des quarks au spin du proton à 0.26<ΔΣ<0.33 à Q² = 3 (GeV/c)² dans le schéma MSbar. L'étude montre que l'incertitude principale sur ΔΣ est liée au choix des formes fonctionnelles utilisées dans la régression des données. Enfin, la règle de somme de Bjorken, qui constitue un test de QCD, est vérifiée avec une précision de 9% en utilisant les données de COMPASS uniquementThe work presented in this thesis is related to the study of the longitudinal spin structure of the nucleon. The aim is to determine the contribution to the spin 1/2 of the proton in terms of its constituents, quarks and gluons. The analysis is performed on the data taken with the COMPASS experiment, which benefits from a polarised muon beam at 200 GeV scattered off polarised protons from an ammonia target of 1.2 m long. The double longitudinal spin asymmetry of deep inelastic scattering cross-Section. The spin-Dependent structure function of the proton g₁p is derived from these measurements, which extend the kinematic world coverage to unexplored region so far (0,0036 < x< 0,57; 1,03 < Q² (GeV/c)² < 96 and 23 < W² (GeV/c)² < 320).The results obtained with a high statistical precision are included in a Next-To-Leading order QCD analysis of world g₁p, g₁d and g₁n (proton, deuteron and neutron) data to parametrise the polarised quark and gluon distributions. The g₁ world coverage of the x and Q² kinematic domain, which is a key point in the sensitivity to the gluon polarisation ΔG, turns out to be too limited for an accurate ΔG determination. Nevertheless, the QCD analysis allows to determine the quark spin contributions to the proton spin to 0.26<ΔΣ<0.33 at Q² = 3 (GeV/c)² in the MSbar scheme. The dominant uncertainty on ΔΣ is related to the choice of functional forms assumed in the fit. Finally, the Bjorken sum rule, which constitutes a fundamental test of QCD, is verified on the COMPASS data alone with a precision of 9%
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Sbrizzai, Giulio. "Measurements of transverse momentum dependent azimuthal asymmetries in SIDIS at COMPASS." Doctoral thesis, Università degli studi di Trieste, 2011. http://hdl.handle.net/10077/4971.
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2009/2010The main topic of this thesis is the measurement of the transverse momentum dependent (TMD) azimuthal asymmetries in the inclusive hadron production in the deep inelastic scattering (DIS). This work has been carried on in the framework of COMPASS, a fixed target experiment at CERN's SPS, which started data taking in 2002. One of the main topic of COMPASS is the study of the nucleon spin structure using high energy (100-200 GeV) muon beam and either transversely and longitudinally polarized proton and deuteron target. Recent developments both from the experimental and theoretical side pointed out the relevance of the transverse spin effects and of new effects, related to the intrinsic transverse momentum of the quark and its correlation with the spin. The nucleon structure, in the non perturbative QCD formalism, can be described at first order, in the collinear approximation, by three parton distribution functions (PDF): the unpolarized PDF, the helicity PDF and the transversity PDF. When including the intrinsic transverse momentum of the quark other 5 PDFs are needed at first order. They are related to the correlation between the transverse momentum of the quark and the spin and are practically unmeasured. The semi inclusive DIS (SIDIS) allows to study all these functions. Indeed the the SIDIS differential cross section, taking into account the beam and target polarization, is characterized by 14 azimuthal modulations in independent linear combination of the nucleon spin angle and of the hadrons angle, as measured with respect to the virtual photon direction. Their amplitudes are related to the structure functions given by the convolution between the new PDFs and the hadron fragmentation functions. In this thesis the measurement of the azimuthal asymmetries which appears in the SIDIS cross section on the unpolarized and longitudinally polarized target. Of particular interest is the information that this measurement give on the Boer-Mulders TMD PDF, which is a very interesting topic. The analysed data have been taken using the 160 GeV positive muon beam on the deuteron target. The target configuration and the spectrometer are optimized for the spin asymmetry measurements and are described in the thesis as well as the data taking. Also, the data processing and the software used for the analysis and the SIDIS data selection are described. The measurement of the azimuthal asymmetries on the longitudinally polarized target have been done using the same data as the one used for the $\Delta$G (the contribution to the nucleon spin of the longitudinal spin of the gluons) measurement. To avoid acceptance effects in the asymmetries extraction, the data collected from the two oppositely polarized target cells (which form the target) have been opportunely combined. Other possible systematic effects have been studied in details and are described in the thesis. \\ The asymmetries have been extracted as functions of the relevant kinematical variables and separately for positive and negative hadrons. The final results, accepted for publication in European Journal C, are compared with the results produced by other experiments and with the calculations of theoretical models of the TMD functions. The measurement of the azimuthal asymmetries which appears in the spin independent part of the SIDIS cross section is more difficult since it cannot benefit from the periodically reversal of the target polarization. The measured hadron azimuthal distributions must be corrected for the possible effects introduced by the apparatus acceptance (geometrical acceptance, detectors and trigger efficiencies). The Monte Carlo simulation of the apparatus has been used to estimate those effects. Extensive studies of the description of the azimuthal acceptance of the apparatus have been done in the whole kinematical domain of interest using different SIDIS events generations. A reliable asymmetries extraction method has been developed and used. A considerable effort has been put into the study and the control of the systematics. Also in this case the asymmetries have been extracted as functions of the relevant kinematical variables and separately for positive and negative hadrons. \\ The strongest measured signals are related to the Cahn effect, which is a kinematical effect proportional to the intrinsic transverse momentum of the quarks, and to the Boer-Mulders TMD PDF, describing the correlation between the intrinsic transverse momentum of the quark and its transverse spin. \\ The results, in particular the kinematical and the charge dependencies of the asymmetries, are interpreted in terms of TMD quantities and higher effects in the non perturbative QCD. The comparisons with the results produced by the other experiments, and with the theoretical predictions are also discussed.
XXIII Ciclo
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Woda, Clemens. "Elektronen-Spin-Resonanz-Datierung von Quarz Grundlagen, Systematik und Anwendungen unter Einbeziehung der Thermolumineszenz /." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=961829885.
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Eldahoumi, Gamal. "Constituent Quarks and the Gluonic Contribution to the Spin of the Nucleon." Diss., lmu, 2009. http://nbn-resolving.de/urn:nbn:de:bvb:19-100441.
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Virey, Jean-Marc. "Asymétries de spin et nouvelle physique auprès de collisionneurs polarisés." Aix-Marseille 1, 1997. http://www.theses.fr/1997AIX11037.
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Dans cette these, nous nous sommes interesses a la mise en evidence de nouveaux phenomenes au-dela du modele standard de la physique des particules. Nous avons montre que l'utilisation d'observables dependant du spin permettra de contraindre severement la presence d'eventuels sous-constituants pour les quarks et les electrons, ainsi que l'existence de nouveaux bosons de spin i, neutres ou charges. De plus, l'etude de ces asymetries de spin permettra, d'une part, de calibrer les differentes distributions polarisees des quarks et des gluons presents au sein des nucleons, et d'autre part, de donner des informations cruciales sur la structure (chirale) d'une eventuelle nouvelle interaction. Nous avons realise notre etude dans le cadre de collisions purement hadroniques (i. E. Proton-proton, proton-antiproton, proton-he 3) ainsi que dans le contexte de la diffusion profondement inelastique polarisee de leptons sur des nucleons.
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Michaud, Yonnel. "Etude phénoménologique de la réaction d'échange de charge (pi)-p -> (pi)[n à haute énergie]." Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10097.
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La presente these est consacree a l'etude de la reaction d'echange de charge pion negatif proton donne pion nul neutron. Cette reaction fait partie des processus quasi-elastiques, caracterises par de petits moments transferes, et donc non interpretables par la chromodynamique quantique. Le modele de glauber, utilise avec succes dans le cadre de la diffusion elastique, est exploite ici pour l'etude de la reaction d'echange de charge. Une interaction effective entre quarks, incluant un terme central et un terme spinorbite, est employee afin de rendre compte de l'echange du meson rho. Les resultats obtenus permettent de conclure a la nature diffractive de la reaction etudiee, mais ne permettent pas de determiner avec precision les rayons moyens des densites de quarks interagissants
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Chanfray, Guy. "Sur quelques problèmes illustrant le rôle des degrés de liberté de quarks et de mésons dans les noyaux." Lyon 1, 1987. http://www.theses.fr/1987LYO19009.
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Riedl, Johann [Verfasser], and Andreas [Akademischer Betreuer] Schäfer. "Spin-dependent hadro- and photoproduction of heavy quarks at next-to-leading order of QCD / Johann Riedl. Betreuer: Andreas Schäfer." Regensburg : Universitätsbibliothek Regensburg, 2014. http://d-nb.info/1050591976/34.
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Hensel, C., K. Johns, X. Lei, R. Nayyar, and E. W. Varnes. "Measurement of spin correlation between top and antitop quarks produced in p(p)over-bar collisions at root s=1.96 TeV." ELSEVIER SCIENCE BV, 2016. http://hdl.handle.net/10150/616988.
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We present a measurement of the correlation between the spins of t and (t) over bar quarks produced in proton-antiproton collisions at the Tevatron Collider at a center-of-mass energy of 1.96 TeV. We apply a matrix element technique to dilepton and single-lepton+jets final states in data accumulated with the DO detector that correspond to an integrated luminosity of 9.7 fb(-1). The measured value of the correlation coefficient in the off-diagonal basis, O-off = 0.89 +/- 0.22 (stat + syst), is in agreement with the standard model prediction, and represents evidence for a top-antitop quark spin correlation difference from zero at a level of 4.2 standard deviations. (C) 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP(3).
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Bensafa, Imad Khaled. "Mesure de l'asymétrie de spin de faisceau en diffusion Compton virtuelle polarisée sur le proton." Clermont-Ferrand 2, 2006. http://tel.archives-ouvertes.fr/docs/00/08/34/67/PDF/bensafa.pdf.
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La première partie présente l'analyse et le résultat de l'expérience VCS-SSA à MAMI (Mayence). Celle-ci a été réalisée avec un faisceau d'energie 883 MeV et de polarisation longitudinale (~80%), à un quadri-moment de transfert (Q2=0. 35 GeV2) pour mesurer l'asymétrie de spin de faisceau dans les réactions ep-epgamma-eppi°. L'asymétrie obtenue en électroproduction de photon (resp. Pion) varie entre 0-15% (resp. 0-2%). Les modèles DR (Relations de Dispersion) pour la diffusion Compton virtuelle et MAID (pi°) prédisent l'amplitude globale de l'asymétrie mais pas complètement. Ce désaccord s'explique peut-être par une paramétrisation imparfaite de certains multipôles de production de pion ( gamma(*)N-piN). La deuxième partie est dédié à l'étude du spectre d'énergie du nucléon dans les états fondamentals L=0 et excité L=1 dans le modèle de quarks, en utilisant le potentiel Coulombien + linéaire (CL) et une correction relativiste. Une correction hyperfine est appliqué pour séparer les masses des nucléons. Les masses trouvées pour le proton et le delta (1232) sont respectivement égales à (968 MeV, 1168 MeV), et les masses des états excités (L = 1) varient entre 1564-1607 MeV. Et le modèle CL est appliqué à un calcul approché des polarisations généralisées du proton
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Hinz, Luc. "Etude expérimentale des performances du module 0 du calorimètre électromagnétique bouchon d'ATLAS : étude de la corrélation de spin dans la production des paires ttbar au LHC." Phd thesis, Université de la Méditerranée - Aix-Marseille II, 2001. http://tel.archives-ouvertes.fr/tel-00001595.
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Jacobsen, Kerstin. "Untersuchung der Struktur und Dynamik von T4 Lysozym auf planaren Oberflächen mittels ESR-Spektroskopie." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2005. http://dx.doi.org/10.18452/15326.
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Es ist eine allgemein akzeptierte Tatsache, dass der Kontakt von Proteinen mit synthetischen Materialien üblicherweise zur Proteinadsorption an der Materialoberfläche führt. Über den stattfindenden Prozess, insbesondere das Zusammenspiel zwischen Protein-Oberflächen-Wechselwirkungen und konformellen Änderungen der adsorbierten Proteine ist jedoch bisher nur wenig bekannt. In dieser Arbeit wird die ortsgerichtete Spinmarkierungstechnik (SDSL) auf die Strukturuntersuchung adsorbierter Proteine ausgeweitet. Diese nutzt das spezifische Einbringen einer spinmarkierte Seitenkette an gewünschte Positionen der Primärstruktur zur Analyse der Struktur und Dynamik diamagnetischer Proteine mittels der Elektronenspinresonanz(ESR)-Spektroskopie. Das globuläre Protein T4 Lysozym (T4L) wurde auf planare Modelloberflächen adsorbiert und strukturelle Änderungen in Abhängigkeit der physikalischen und chemischen Eigenschaften der Oberfläche verfolgt. Die spezifische Anbindung von T4L auf quarzgestützten zwitterionische Lipiddoppelschichten führt nur zu geringfügigen strukturellen Veränderungen des Proteins. Allerdings bildet sich eine makroskopisch geordnete Proteinschicht aus. Die Vorzugsrichtung der Proteine auf der Oberfläche kann durch Analyse der winkelabhängigen ESR-Spektren bestimmt werden. Die Wechselwirkung negativ geladener Oberflächen mit dem positiv geladenen T4L führt zu drastischeren Störungen der Proteinstruktur. Hierbei wird die Reaktion des Proteins auf den Kontakt mit einer fluiden quarzgestützten Lipiddoppelschicht, die das negativ geladenen Lipid Phosphatidylserin enthält, mit derer bei Adsorption auf einer ebenfalls negativ geladenen, jedoch rigiden Quarzoberfläche verglichen. Dass der Adsorptionsprozess auch das Substrat selbst beeinflussen kann, wird durch die Beobachtung einer Phasentrennung bei Proteinadsorption des Lipidgemischs aufgezeigt, das negativ geladene Lipide enthält.Although it is commonly accepted that the exposition of proteins to man-made materials typically results in protein adsorption on the material surface, little is known about the interplay between the protein-surface interactions involved and the resulting conformational changes of the adsorbing protein. In this study the site-directed spin labeling (SDSL) approach has been extended to the investigation of proteins adsorbed to planar surfaces. The method involves the selective introduction of an artificial spin-labeled side-chain to a predefined residue of the amino acid sequence and allows the determination of the structure and dynamics of proteins by analysis of the electron paramagnetic resonance (EPR) spectra. The globular protein T4 Lysozyme (T4L) has been adsorbed to planar model surfaces to study the correlation between conformational changes of the protein and the physical and chemical properties of the surfaces. Tethering T4L to a planar quartz-supported zwitterionic lipid bilayer shows only minor changes in the structure of the protein. Furthermore, a macroscopic order of the adsorbed protein layer is proven by angular-dependent EPR spectra which allow the determination of the protein orientation. Offering surfaces that are net negatively charged to the highly positively charged T4L leads to the observation of more drastic conformational changes. Here, the conformation of T4L adsorbing to a fluid quartz-supported lipid bilayer containing negatively charged lipids is compared to the structure of T4L adsorbed to the negatively charged but rigid quartz surface. The adsorption process may also influence the substrate itself. This can be shown by the phase separation of the negatively charged lipid bilayer upon protein adsorption.
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Lemmer, Boris. "Measurement of Spin Correlations in Top/Anti-Top Events from pp Collisions at sqrt(s) = 7 TeV in the Lepton+Jets Final State with the ATLAS Detector." Doctoral thesis, 2014. http://hdl.handle.net/11858/00-1735-0000-0023-98DC-5.
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Das Top-Quark zerfällt, bevor es hadronisiert. Bevor die Spin-Konfiguration des Top-Quarks durch Prozesse der Starken Wechselwirkung geändert werden kann, wird sie direkt an die Zerfallsprodukte des Top-Quarks weitergegeben. Rückschl usse auf den Spin des Top-Quarks können über Winkelverteilungen der Zerfallsprodukte gezogen werden. Die Spins von Top-/Anti-Top-Quark (tt) Paaren sind, gemäß der Vorhersage durch das Standardmodell, korreliert. Der Grad der Korrelation ist sensitiv auf den Spin und die Produktionsmechanismen des Top-Quarks. Die Messung der Spin-Korrelation bietet einen Test der Vorhersagen. Effekte von Physik jenseits des Standardmodells können sich in Abweichungen der vorhergesagten Spin-Korrelation manifestieren. In dieser Arbeit wird die Spin-Korrelation von Top-Quark Paaren, die bei einer Schwerpunktsenergie von sqrt(s) = 7 TeV produziert und mit dem ATLAS Detektor rekonstruiert wurden, gemessen. Der Datensatz entspricht einer integrierten Luminosität von 4.6 fb-1. Die Top-Quarks wurden im Lepton+Jets Zerfallskanal mittels eines kinematischen Likelihood-Fits, der eine Trennung der leichten up- und down-Typ Quarks aus dem t->bW->bqq Zerfall erlaubt, rekonstruiert. Die Spin-Korrelation wird über die Verteilung des Azimutalwinkels zwischen zwei Top-Quark Spin-Analysatoren im Laborsystem gemessen. Sie wird als Grad fSM der Spin-Korrelation, wie sie im Rahmen des Standardmodells berechnet wird, angegeben. Die Messungen ergeben fSM(DeltaPhi(geladenes Lepton, down-Typ Quark)) = 1.53 ± 0.14 (stat.) ± 0.32 (syst.); fSM(DeltaPhi(geladenes Lepton, b-Quark)) = 0.53 ± 0.18 (stat.) ± 0.49 (syst.); fSM(DeltaPhi(kombiniert)) = 1.12 ± 0.11 (stat.) ± 0.22 (syst.). Die Ergebnisse stimmen mit der Berechnung im Rahmen des Standardmodells, fSM = 1.0, überein.
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Schmitt, Andreas [Verfasser]. "Spin-one color superconductivity in cold and dense quark matter / von Andreas Schmitt." 2004. http://d-nb.info/974955094/34.
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Kayanikhoo, Fatemeh. "Calculation of the thermodynamic properties of the spin polarized strange quark star in the presence of strong magnetic field." Master's thesis, 2012. http://hdl.handle.net/10316/98847.
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Documentos apresentados no âmbito do reconhecimento de graus e diplomas estrangeirosIn this thesis, we investigated the strange quark matter (SQM) composed of the spin-up and spin-down; up, down and strange quarks at finite temperature in the presence of the strong magnetic field using the MIT bag model. We computed the total free energy of the spin polarized SQM at finite temperature in the presence of the strong magnetic field. We found that the free energy gets a minimum at a particular value of the spin polarization parameter showing a meta-stable state. The calculation shown that by increasing temperature, the equation of state of spin polarized SQM becomes stiffer. Also, using the general relativistic TOV equation, we studied the structure of the spin polarized strange quark star (SQS). We calculated the maximum mass and corresponding radius of spin polarized SQS at different temperatures and magnetic fields. We shown that the gravitational mass of spin polarized SQS rapidly increases by increasing the central energy density. We also indicated that the mass and the radius of the spin polarized SQS decreases by increasing both temperature and magnetic field.
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Lu, Shaojun [Verfasser]. "Measurement of the strange quark contribution to the proton spin using neutral kaons at HERMES / vorgelegt von Shaojun Lu." 2007. http://d-nb.info/984199861/34.
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Sun, Xiaohu. "Mesure de la polarisation dans la production électrofaible de quark top avec le détecteur ATLAS." Phd thesis, 2013. http://tel.archives-ouvertes.fr/tel-00873541.
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La polarisation des quarks top produit par interaction électrofaible permet de sonder la structure du vertex Wtb et en particulier de tester le couplage vecteur gauche prévu dans le cadre du Modèle Standard et de rechercher les couplages anormaux droit et tenseur introduits par plusieurs théories au-delà du Modèle Standard. Cette thèse présente la mesure de la polarisation des quarks top produits par interaction électrofaible à partir des données correspondantes à une luminosité integrée de 4,7 fb-1 enregistrées en 2011 par le détecteur ATLAS dans les collisions proton-proton du LHC à l'énergie centre de masse de 7 TeV. La polarisation est extraite des distributions angulaires reconstruites dans une base de spin spécifique pour les événements de production de quark top en voie-t. Le contexte théorique de production de quarks top par interactions forte et électrofaible dans les collisionneurs hadroniques est tout d'abord introduit. Ensuite, le détecteur, les performances de reconstruction des objets physiques ainsi que la sélection des événements avec une signature de top quark électrofaible en voie-t sont décrits. Les méthodes de déconvolution et de convolution utilisées pour extraire la polarisation sont ensuite présentées et testées avec différentes configurations. Les résultats obtenus ainsi que les incertitudes théoriques, expérimentales et statistiques sont finalement examinées. Cette thèse présente la première mesure avec le détecteur ATLAS de la polarisation des quarks top électrofaibles. Les résultats obtenus sont compatibles avec les prédictions du Modèle Standard et contribueront à contraindre de manière significative les couplages Wtb anormaux.
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Kravchenko, Polina [Verfasser]. "The final inclusive and semi-inclusive longitudinal double-spin asymmetries at HERMES : extraction of quark helicity distributions of the nucleon from deep-inelastic scattering / vorgelegt von Polina Kravchenko." 2010. http://d-nb.info/1008770345/34.
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Eldahoumi, Gamal [Verfasser]. "Constituent quarks and the gluonic contribution to the spin of the nucleon / submitted by Gamal Eldahoumi." 2009. http://d-nb.info/994428715/34.
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Woda, Clemens [Verfasser]. "Elektronen-Spin-Resonanz-Datierung von Quarz : Grundlagen, Systematik und Anwendungen unter Einbeziehung der Thermolumineszenz / vorgelegt von Clemens Woda." 2000. http://d-nb.info/961829885/34.
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Furget, Christophe. "Observables de spin en physique hadronique et facteurs de forme du deuton et du proton." Habilitation à diriger des recherches, 2002. http://tel.archives-ouvertes.fr/tel-00001751.
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