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1	Les anomalies fortes et électromagnétiques dans les désintégrations faibles des mésons Trine, Stéphanie 06 December 2004 (has links) Les effets des opérateurs liés aux anomalies axiale et de trace de QCD et de QED dans les désintégrations faibles des mésons sont analysés dans deux régimes extrêmes: tout d'abord lorsque les densités anomales de gluons et de photons sont générées à courte distance par une boucle de quark lourd, ensuite lorsqu'elles sont générées à longue distance par des corrections fortes associées aux quarks légers u, d et s. A courte distance, l'ensemble des corrections de type pingouin à une interaction effective à quatre quarks arbitraire est obtenu à partir de l'expansion en la masse inverse du propagateur d'un quark lourd plongé dans un champ de jauge classique. Une suppression des effets anomaux est ainsi mise en évidence dans le Modèle Standard. Un nouvel ensemble d'opérateurs de dimension huit décrivant les effets du quark charmé dans les désintégrations des kaons est également établi. A longue distance, les effets anomaux associés aux quarks légers dans les désintégrations faibles hadroniques et radiatives des kaons sont analysés dans le formalisme des Lagrangiens chiraux. Une contribution potentiellement importante de l'opérateur d'anomalie de trace est ainsi mise en évidence. Les implications d'une éventuelle dominance des anomalies sont également étudiées. Effective Lagrangian Anomaly Kaon Heavy quark integration OPE Chiral theories
2	Charmonium absorption and charmed hadron production in hadronic reactions Liu, Wei 17 February 2005 (has links) A gauged SU(4) ﬂavor symmetric hadronic Lagrangian with empirical hadron masses is constructed to study charmonium absorption and charmed hadron production in hadronic reactions. For the coupling constants, empirical values are used if available. Otherwise, they are determined from known coupling constants using the SU(4) relations. To take into account the ﬁnite sizes of hadrons, form factors are introduced at strong interaction vertices with empirical cutoff parameters. For J/ψabsorption by nucleons, we have included both two-and three-body final states and ﬁnd that with a cutoff parameter of 1 GeV at interaction vertices involving charm hadrons, the cross section is at most 5 mb and is consistent with that extracted from J/ψproduction from both photo-and proton-nucleus reactions. We have also evaluated the cross sections for charmed hadron production from pion and rho meson interactions with nucleons. With the same cutoff parameter of 1 GeV at interaction vertices, we ﬁnd that these cross sections have values of a few tenths of mb and are dominated bythe s-channel nucleon pole diagram. For charmed hadron production from proton-proton reactions, their cross sections including bothtwo-andthree-body ﬁnal states are about 1 batcenter-of-mass energyof 11.5 GeV, which is comparable to the measured inclusive cross section in these reactions.Including photon as a U(1) gauge particle, we have extended the model to study charmed hadron production in photon-proton reactions with both two-and three-body ﬁnal states included. For form factors, an overall one is introduced in each processin order to maintain the gauge invariance of the total amplitude. Fitting the cutoff parameter in the form factor to the measured total cross section for charmed hadron production in photon-proton reactions at a center-of-mass energy of 6 GeV, the ratio of the cross sections for two-body and three-body ﬁnal states is consistent with available experimental data.This result is further compared with predictions from the leading-order perturbative QCD calculation. Knowledge of the cross sections for charmonium absorption byhadrons and for charmed hadron production in hadronic reactions is essential for understanding charm production in heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC), where a quark-gluon plasma is expected to be formed during the initial hot dense stage. charmonium SU(4) symmetry photoproduction absorption effective Lagrangian form factor
3	Charmonium absorption and charmed hadron production in hadronic reactions Liu, Wei 17 February 2005 (has links) A gauged SU(4) ﬂavor symmetric hadronic Lagrangian with empirical hadron masses is constructed to study charmonium absorption and charmed hadron production in hadronic reactions. For the coupling constants, empirical values are used if available. Otherwise, they are determined from known coupling constants using the SU(4) relations. To take into account the ﬁnite sizes of hadrons, form factors are introduced at strong interaction vertices with empirical cutoff parameters. For J/ψabsorption by nucleons, we have included both two-and three-body final states and ﬁnd that with a cutoff parameter of 1 GeV at interaction vertices involving charm hadrons, the cross section is at most 5 mb and is consistent with that extracted from J/ψproduction from both photo-and proton-nucleus reactions. We have also evaluated the cross sections for charmed hadron production from pion and rho meson interactions with nucleons. With the same cutoff parameter of 1 GeV at interaction vertices, we ﬁnd that these cross sections have values of a few tenths of mb and are dominated bythe s-channel nucleon pole diagram. For charmed hadron production from proton-proton reactions, their cross sections including bothtwo-andthree-body ﬁnal states are about 1 batcenter-of-mass energyof 11.5 GeV, which is comparable to the measured inclusive cross section in these reactions.Including photon as a U(1) gauge particle, we have extended the model to study charmed hadron production in photon-proton reactions with both two-and three-body ﬁnal states included. For form factors, an overall one is introduced in each processin order to maintain the gauge invariance of the total amplitude. Fitting the cutoff parameter in the form factor to the measured total cross section for charmed hadron production in photon-proton reactions at a center-of-mass energy of 6 GeV, the ratio of the cross sections for two-body and three-body ﬁnal states is consistent with available experimental data.This result is further compared with predictions from the leading-order perturbative QCD calculation. Knowledge of the cross sections for charmonium absorption byhadrons and for charmed hadron production in hadronic reactions is essential for understanding charm production in heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC), where a quark-gluon plasma is expected to be formed during the initial hot dense stage. charmonium SU(4) symmetry photoproduction absorption effective Lagrangian form factor
4	Brisure CP/T via les produits triples dans les désintégrations des hadrons à saveur de beauté Bensalem, Wafia 05 1900 (has links) Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal. / Cette thèse est constituée de quatre articles qui ont tous été publiés. Le sujet principal est l’étude d’asymétries de brisure CP/T via les produits triples dans les désintégrations des hadrons contenant un quark b (mésons B ou hypérons Ab) et ce, dans le modèle standard de la physique des particules et au-delà. / This thesis is comprised of four articles, ail of which have been published. The main subject is the study, in and beyond the standard model of particle physics, of CP/T-violation via triple products in decays of hadrons containing a b quark (B mesons or Ab hyperons). Modèle standard Nouvelle physique Spin Polarisation Parité Conjugaison de charge Renversement du sens du temps Asymétrie avant-arrière Lagrangien efficace Modèle de factorisation Standard model New physics Symmetry Triple product Polarization CP/T-violation Decay Forward-backward asymmetry Effective lagrangian Factorization model
5	Probing Electroweak Gauge Boson Scattering with the ATLAS Detector at the Large Hadron Collider Anger, Philipp 07 October 2014 (has links) (PDF) Electroweak gauge bosons as central components of the Standard Model of particle physics are well understood theoretically and have been studied with high precision at past and present collider experiments. The electroweak theory predicts the existence of a scattering process of these particles consisting of contributions from triple and quartic bosonic couplings as well as Higgs boson mediated interactions. These contributions are not separable in a gauge invariant way and are only unitarized in the case of a Higgs boson as it is described by the Standard Model. The process is tied to the electroweak symmetry breaking which introduces the longitudinal modes for the massive electroweak gauge bosons. A study of this interaction is also a direct verification of the local gauge symmetry as one of the fundamental axioms of the Standard Model. With the start of the Large Hadron Collider and after collecting proton-proton collision data with an integrated luminosity of 20.3/fb at a center-of-mass energy of 8 TeV with the ATLAS detector, first-ever evidence for this process could be achieved in the context of this work. A study of leptonically decaying WWjj, same-electric-charge diboson production in association with two jets resulted in an observation of the electroweak WWjj production with same electric charge of the W bosons, inseparably comprising WW->WW electroweak gauge boson scattering contributions, with a significance of 3.6 standard deviations. The measured production cross section is in agreement with the Standard Model prediction. In the course of a study for leptonically decaying WZ productions, methods for background estimation, the extraction of systematic uncertainties and cross section measurements were developed. They were extended and applied to the WZjj final state whereof the purely electroweakly mediated contribution is intrinsically tied to the scattering of all Standard Model electroweak gauge bosons: Wγ->WZ and WZ->WZ. Three charged leptons and a neutrino from the decay of the final state bosons allow inferences about the scattering process. A distinct signature is provided by the two accompanying tagging jets as remnants of the incoming quarks radiating the initial electroweak gauge bosons. The cross section of the electroweak WZjj production was measured to σ(fiducial, observed) = (0.63 +0.32 -0.28 (stat.) +0.41 -0.24 (syst.)) fb and was found to be consistent with the Standard Model prediction at next-to-leading order in perturbative quantum chromodynamics, σ(fiducial, theory) = (0.31 +0.03 -0.05) fb. Unfolded differential cross sections of kinematic variables sensitive to models of new physics were derived. Anomalous quartic electroweak gauge couplings are introduced as dimensionless coupling parameters of additional operators within an effective field theory approach. Constraints on the parameters of operators with dimension eight were set employing a unitarization prescription based on form factors. CERN LHC ATLAS 2014 Standardmodell Teilchenphysik Elementarteilchenphysik VBS Eichboson-Streuung Vektorboson-Streuung Vektor-Boson-Streuung aQGC aqgc anomale Eichkopplung anomale Vierer-Eichboson-Kopplung Effektive Lagrangedichte Vierer-Vertex Vierer-Eichboson-Vertex Higgs WZ-Endzustand Sherpa VBFNLO Whizard K-Matrix Form-Faktor Formfaktor Unitarisierung Boson CERN LHC ATLAS 2014 Standard Model Particle Physics VBS Vector Boson Scattering Vector-Boson-Scattering Vector-Boson Scattering Gauge Boson Scattering Electroweak Gauge Boson Scattering aQGC aqgc Anomalous Quartic Gauge Boson Coupling Anomalous Gauge Boson Coupling Effective Lagrangian Quartic Vertex Quartic Gauge Boson Vertex Higgs WZ Final State Sherpa VBFNLO Whizard K-Matrix Form-Factor Unitarization Unitarisation Boson ddc:530 rvk:UO 6420 CERN LHC 2014 Elementarteilchenphysik Boson
6	Probing Electroweak Gauge Boson Scattering with the ATLAS Detector at the Large Hadron Collider Anger, Philipp 01 September 2014 (has links) Electroweak gauge bosons as central components of the Standard Model of particle physics are well understood theoretically and have been studied with high precision at past and present collider experiments. The electroweak theory predicts the existence of a scattering process of these particles consisting of contributions from triple and quartic bosonic couplings as well as Higgs boson mediated interactions. These contributions are not separable in a gauge invariant way and are only unitarized in the case of a Higgs boson as it is described by the Standard Model. The process is tied to the electroweak symmetry breaking which introduces the longitudinal modes for the massive electroweak gauge bosons. A study of this interaction is also a direct verification of the local gauge symmetry as one of the fundamental axioms of the Standard Model. With the start of the Large Hadron Collider and after collecting proton-proton collision data with an integrated luminosity of 20.3/fb at a center-of-mass energy of 8 TeV with the ATLAS detector, first-ever evidence for this process could be achieved in the context of this work. A study of leptonically decaying WWjj, same-electric-charge diboson production in association with two jets resulted in an observation of the electroweak WWjj production with same electric charge of the W bosons, inseparably comprising WW->WW electroweak gauge boson scattering contributions, with a significance of 3.6 standard deviations. The measured production cross section is in agreement with the Standard Model prediction. In the course of a study for leptonically decaying WZ productions, methods for background estimation, the extraction of systematic uncertainties and cross section measurements were developed. They were extended and applied to the WZjj final state whereof the purely electroweakly mediated contribution is intrinsically tied to the scattering of all Standard Model electroweak gauge bosons: Wγ->WZ and WZ->WZ. Three charged leptons and a neutrino from the decay of the final state bosons allow inferences about the scattering process. A distinct signature is provided by the two accompanying tagging jets as remnants of the incoming quarks radiating the initial electroweak gauge bosons. The cross section of the electroweak WZjj production was measured to σ(fiducial, observed) = (0.63 +0.32 -0.28 (stat.) +0.41 -0.24 (syst.)) fb and was found to be consistent with the Standard Model prediction at next-to-leading order in perturbative quantum chromodynamics, σ(fiducial, theory) = (0.31 +0.03 -0.05) fb. Unfolded differential cross sections of kinematic variables sensitive to models of new physics were derived. Anomalous quartic electroweak gauge couplings are introduced as dimensionless coupling parameters of additional operators within an effective field theory approach. Constraints on the parameters of operators with dimension eight were set employing a unitarization prescription based on form factors. info:eu-repo/classification/ddc/530 ddc:530

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