Dissertations / Theses: 'Semileptonic decay'

1

Lai, I. Chung. "Measurement of bar{B0} Meson Properties Via Partial Reconstruction of the Decay bar{B0} -> D*+ l- ar{nu}." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/38697.

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Using data recorded by the CLEO II detector operating at the Upsilon(4S) resonance at the Cornell Electron Storage Ring, several properties of B mesons are measured using a partially reconstructed tag of the decay mode bar{B0} -> D*+ l- bar{nu}. Using 2.38 fb**{-1} of on-resonance data and the averaged B meson semileptonic branching fraction through inclusive lepton momentum spectrum obtained by previous CLEO analysis, we measure the B0 and B- semileptonic branching fraction to be (10.78 +/- 0.60 +/- 0.69)% and (10.25 +/- 0.57 +/- 0.65)% respectively, which yields the lifetime ratio tau_+/tau_0 = 0.950 +0.117-0.080 +0.091-0.068, assuming the equality of semileptonic partial branching width for bar{B0} and B-. With a larger dataset of 3.1 fb**{-1}, we measured the B0-bar{B0} mixing parameter chi_d to be 0.189 +/- 0.019 +/- 0.006.
Ph. D.

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2

Lipeles, Elliot Weinstein Alan Jay. "A study of the fully differential inclusive semileptonic B Meson decay rate /." Diss., Pasadena, Calif. : California Institute of Technology, 2004. http://resolver.caltech.edu/CaltechETD:etd-05102004-100412.

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3

Godang, Romulus. "Measurement of the Ratio of Charged and Neutral 𝐵 Mesons in Υ (4𝑆) Events via Partial Reconstruction of the Semileptonic Decays 𝛣̅⁰⟶𝐷^∗⁺ℓ⁻_𝜈̅ℓ and 𝛣̅⁻⟶𝐷^∗⁰ℓ_𝜈̅ℓ." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/28846.

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The decays,

and

are studied using data collected at the CLEO II detector at the Cornell Electron Storage Ring. Both decays are identified using a partial reconstruction method where the D^* is detected only through a pion daughter from the decay

. Because of the similarities in the analyses of the two modes, the ratio of the rates is measured in a way that is independent of the decay model, limited mainly by the uncertainty in the relative efficiency for detecting neutral and charged pions. This ratio is equivalent to the ratio of the product of production fraction and lifetime for charged and neutral B mesons,

. It is combined with measurements of the lifetime ratio to obtain the ratio of charged and neutral B meson production at the Y(4S) resonance,

.
Ph. D.

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4

Firmino, da Costa Joa︢o. "Study of the semileptonic decay D໋ →Kֿ π໋ e໋ v໋ with the BaBar experiment." Paris 11, 2009. http://www.theses.fr/2009PA112114.

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L'intérêt de cette thèse consiste dans l'étude du système hadronique Kπ avec I=1/2 (isospin) à basse énergie depuis son seuil de création. En utilisant un formalisme qui utilise un développement en ondes partielles selon le moment angulaire, nous sommes en mesure d'étudier les différentes composantes de ce système. On caractérise entièrement ce canal. Grâce à 5 variables, iI s'agit d'une analyse à 5 dimensions. Cette analyse est réalisée en utilisant une approche dite « untagged » de reconstruction ce qui nous permet de garder un grand nombre d'événements de signal. La difficulté dans cette analyse est l'existence de bruit de fond non négligeable dont il faut bien comprendre ses caractéristiques. Pour cela des études spécifiques ont été réalisées en utilisant des échantillons particuliers de données et de simulation. La méthode permettant l'extraction des paramètres intéressants aux modèles que l'on veut tester consiste à utiliser un maximum de vraisemblance entre les données et la simulation où les échantillons respectifs sont divisés en 2800 bins suivant les 5 dimensions. Des tests intensifs pour cette méthode ont été réalisés en utilisant des pseudos expériences ainsi que la simulation complète des données BaBar a été réalisée et la valident. On a pu déterminer pour la première fois le comportement de l'onde S du système Kπ depuis le seuil. Les résultats de cette thèse incluent aussi les mesures les plus précises des facteurs de forme hadroniques pour l'onde P ainsi qu'une caractérisation très précise de l'onde P
The interest of this thesis consist in the study of the hadronic system Kπ with I= 1/2(isospin) at low energy starting at its threshold. Using a formalism that takes advantage of a partial wave development according to angular momentum, we are able to study the different components of this system. We characterize completely this channel thanks to 5 variables. It is a 5 dimension analysis. This thesis is performed using an « untagged » approach for reconstruction which allows us to keep a greater number of signal events. The difficulty of this analysis is the existence of non negligible background which needs to be well understood. For this purpose, specific studies have been performed using special samples of data and simulation. The method allowing extracting-interesting parameters from the models one wants to test consists of using a maximum likelihood between data and simulation where the corresponding samples are divided in 2800 bins in the 5 dimensions. Intensive tests for this method have been made using toy simulations as well as complete BaBar simulation and have validated it. I have been able to determine for the first time the behavior of the S-wave for the Kπ system from threshold. The results of this thesis include as well the most precise measurements of the hadronic form factors for the P wave as well as a very precise characterization of the P wave

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5

Mcgregor, Grant Duncan. "Calibration of the LHCb VELO detector and study of the decay mode D0->K-mu+nu_mu." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/calibration-of-the-lhcb-velo-detector-and-study-of-the-decay-mode-d0kmunumu(0c958072-451d-49b1-a6a0-a6e2683d087d).html.

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The LHCb experiment, based at the Large Hadron Collider at CERN, is primarily designed to make precision measurements of the decays of heavy flavour hadrons, such as B and D mesons. This thesis is composed of two parts: the first consists of two studies of LHCb's vertex locator (VELO) and the second describes the development of methods for recording the decay D0->K-mu+nu_mu. The first VELO study involves calibration and monitoring of the gain (i.e. the detector response to input charge from particles). We propose a robust method to measure the gain response of each silicon sensor using calibration bits output by the sensors, and a method to recalibrate the gain simple enough to be followed by non-expert VELO users. This is followed by an investigation into into the prospects of using the VELO to perform particle identification using the characteristic energy deposition of each particle species (dE/dx). Finally, studies into the development of a trigger and a so-called 'stripping line' for recording D0->K-mu+nu_mu decays is presented. The relatively high cross-section for charm decays in LHCb mean this decay (with a branching fraction of 3%) occurs frequently, and the challenge of a trigger is to reduce this to a rate acceptable to write to disk. Finally, based on a sample of data from July and August 2011, the measured q 2 distribution for this decay is compared to the simple single-pole theoretical model, and the pole mass is measured to bem_pole=2.35 + 0.81 - 0.35 GeV/c 2.

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6

Davis, Adam C. "Search for Mixing and Charge Parity Violation in Neutral Charm Mesons through Semileptonic B Meson Decay." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470671480.

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7

Haefner, Petra. "Measurement of the Top Quark Mass with the Matrix Element Method in the Semileptonic Decay Channel at D0." Diss., lmu, 2008. http://nbn-resolving.de/urn:nbn:de:bvb:19-93114.

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8

Kang, Xian-Wei [Verfasser]. "Chiral Dynamics and Final State Interactions in Semileptonic B Meson Decay and Antinucleon-Nucleon Scattering / Xian-Wei Kang." Bonn : Universitäts- und Landesbibliothek Bonn, 2014. http://d-nb.info/1238687415/34.

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9

Lück, Thomas. "Determination of the CKM-matrix element |Vub| from the electron energy spectrum measured in inclusive B -> X u e[Ypsilon] decay with the BABAR detector." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2013. http://dx.doi.org/10.18452/16718.

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Dieses Dokument präsentiert eine Messung des CKM Matrixelementes Vub in inklusiven semileptonischen B nach Xu e nu Ereignissen, auf einem Datensatz von 471 Millionen BB Ereignissen, aufgezeichnet vom BABAR Detektor. Inklusive B nach Xu e nu Zerfälle wurden selektiert indem hochenergetische Elektronen (Positronen) rekonstruiert wurden. Untergrundunterdrückung wurde erreicht indem Ereignisse selektiert wurden mit Elektron- (Positron-) Energien in der Nähe des kinematischen Endpunktes von B nach Xu e nu Zerfällen. Ein Veto für B nach Dstern e nu wurde angewendet um den Untergrund weiter zu reduzieren. Dieses Veto benutzt Dstern Mesonen die mit einer Partiellen Rekonstruktionstechnik rekonstruiert wurden.
This document presents a measurement of the CKM matrix-element Vub in inclusive semileptonic B to Xu e nu events on a dataset of 471 million BB events recorded by the BABAR detector. Inclusive B to Xu e nu decays are selected by reconstructing a high energetic electron (positron). Background suppression is achieved by selecting events with electron (positron) energies near the kinematical allowed endpoint of B to Xu e nu decays. A B to Dstar e nu veto is applied to further suppress background. This veto uses Dstar mesons which have been reconstructed with a partial reconstruction technique.

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10

Haas, Benjamin. "QCD sur réseau et physique du charme." Paris 11, 2009. http://www.theses.fr/2009PA112359.

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Dans cette thèse, nous présentons les résultats des études sur les propriétés de la physique du charme sur le réseau. Nous utilisons des configurations unquenched et une action de quark de type Wilson (Wilson-clove et Wilson twisted). Nous avons étudié la désintégration du meson D* et calculés la valeur du couplage hadronique g_{D* D\pi}$$ et du couplage $$g_{D^\ast D\gamma}$$. Nous avons également étudiés la désintégration leptonic et semilleptonic du méson Ds. Nous avons pu contraindre les éléments $$\vert V_{cd}\vert$$ et $$\vert V_{cs} \vert$$ de la matrice CKM
Ln this thesis, we present the results of the study of the charm properties on the lattice. We used unquenched configuration with Wilson-like actions, i. E. Wilson--Clover and twisted-mass quark actions. We studied the decay of the $$D"\ast$$ meson and computed the coupling hadronic coupling $$g_{D"\ast D\pi}$$,the radiative coupling $$g_{D"\ast D\gamma}$$. We then studied the leptonic and semileptonic of the $$D_{(s)}$$-mesons. We constrained the CKM matrix entries $$\vert V_{cd} \vert$$ and $$\vert V_{cs} \vert$$

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11

Feigl, Bastian [Verfasser], and D. [Akademischer Betreuer] Zeppenfeld. "Electroweak Processes in the Standard Model and Beyond: Backgrounds to Higgs Physics and Semileptonic Decay Modes / Bastian Feigl. Betreuer: D. Zeppenfeld." Karlsruhe : KIT-Bibliothek, 2013. http://d-nb.info/1044956194/34.

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12

Kozeiha, Mohamad. "Search for T violation and CP violation in the Weak Semileptonic Λ0b and Λ+c Decays with the LHCb Detector." Thesis, Université Clermont Auvergne‎ (2017-2020), 2017. http://www.theses.fr/2017CLFAC103/document.

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13

Acar, Hilal. "The Inclusive Semileptonic Decays Of The B-meson In A Cp Softly Broken Two Higgs Doublet Model." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12604766/index.pdf.

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In this work, the B->
X_dell ell decays are examined in the context of a CP softly broken two Higgs doublet model. The differential branching ratio, forward-backward asymmetry, CP-violating asymmetry, CP-violating asymmetry in the forward-backward asymmetry and polarization asymmetries of the final lepton in this decay are studied. The dependencies of these physical parameters on the model parameters are analyzed by paying a special attention to the effects of neutral Higgs boson (NHB) exchanges and possible CP violating effects. It has been found that NHB effects are quite significant for the tau mode and the above-mentioned observables seems to be promising as a testing ground for new physics beyond the SM, especially for the existence of the CP-violating phase in the theory.

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14

Evans, Martin David Treharne. "Charm hadron production in semileptonic b decays and the relative production fractions of weakly decaying b hadrons at the Zâ° resonance." Thesis, Queen Mary, University of London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325676.

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Yilmaz, Umit Oktay. "The Polarization Properties Of The Final State Particles In The Rare Radiative B-meson Decay." Phd thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606100/index.pdf.

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A general analysis of the photon and lepton polarizations in the rare Bs &
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l+l- decay by using the most general model independent form of the effective Hamiltonian is presented. The total and the differential branching ratios for these decays, when photon is in the positive and negative helicity states, are studied. The sensitivity of "
photon polarization asymmetry"
and the longitudinal, transverse and normal polarization asymmetries of final state leptons, as well as lepton-antilepton combined asymmetries in Bs &
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l+l- decay to the new Wilson coefficients are also investigated. It is shown that all these physical observables are very sensitive to the existence of new physics beyond SM and their experimental measurements can give valuable information about it.

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16

Spettel, Fabian M. [Verfasser], Siegfried [Akademischer Betreuer] [Gutachter] Bethke, and Stephan [Gutachter] Paul. "Measurement of the boosted WW+WZ production cross section in the semileptonic decay channel with ATLAS / Fabian M. Spettel ; Gutachter: Stephan Paul, Siegfried Bethke ; Betreuer: Siegfried Bethke." München : Universitätsbibliothek der TU München, 2017. http://d-nb.info/1126644196/34.

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17

Raeven, Barbara Maartje. "Measurements of the mass and width of W boson from e'+e'- -> W'+W'- -. (e/#mu#)#nu#qq'- events with the ALEPH detector." Thesis, University of Glasgow, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325433.

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18

Bernlochner, Florian. "Determination of the CKM matrix element |V cb|, the B -> X s gamma decay rate, and the b-quark mass." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät II, 2012. http://dx.doi.org/10.18452/16565.

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In dieser Arbeit wird die Messung zweier fundamentaler Parameter des Standardmodells der Teilchenphysik diskutiert: der Betrag des CKM Matrixelements Vcb und die b-Quarkmasse.
In this work, the preliminary measurements of two fundamental parameters of the Standard Model of particles physics are presented: the CKM matrix element Vcb, and the b-quark mass.

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Cao, Lu [Verfasser], James Lambrecht [Gutachter] Ritman, and Ulrich [Gutachter] Wiedner. "Simulation of the Ds semileptonic decay with the P̄ANDA detector and experimental verification of the micro-vertex-detector pixel readout ASIC with proton test beam / Lu Cao ; Gutachter: James Lambrecht Ritman, Ulrich Wiedner." Bochum : Ruhr-Universität Bochum, 2016. http://d-nb.info/1114497053/34.

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20

Bates, Martin Joseph. "The performance of the barrel muon trigger system of the DELPHI experiment, and a study of heavy flavour physics through the semileptonic decay to muons in e'+e'- collisons at the Z'o resonance." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314840.

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21

Lee, Jik. "Semileptonic decays of Ds+ Meson /." The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487936356158806.

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22

Gratrex, James. "Rare radiative and semileptonic B meson decays." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/33173.

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Recent results at the LHCb and B-factory experiments have suggested that rare processes in B →Vγ and B → V ℓ¯ℓ decays, where V is a vector meson, show some deviation from Standard Model predictions. Although these anomalies are not yet at the level to constitute a formal discovery, they are certainly suggestive of potential New Physics effects in flavour-changing neutral currents. However, explanations within the Standard Model cannot yet be ruled out. This thesis contributes to the understanding of such anomalies in two ways. Firstly, the angular distribution of the B → KJ (→ Kπ)ℓ1¯ℓ2 decay is derived, for the full dimension-six effective weak Hamiltonian, using a generalisation of the helicity formalism to effective theories mediating b → sℓ1¯ℓ2 transitions. This approach sheds light on the origin of the underlying structure, and in the process extends the general angular distribution to decays in which the two leptons in the final state, ℓ1¯ℓ2, are not necessarily identical. An additional benefit of the derivation of the angular distribution presented in this manner is that it lends itself to a moments analysis of the decay. It is shown how the angular distribution changes in the presence of new operators, predicted to be vanishingly small in the Standard Model. Such operators could be sizeable in the presence of New Physics, but using a moments analysis enables the contribution of such operators to be assessed. Secondly, an analysis is presented of the three-particle vector and axial meson distribution amplitudes. It is shown that the distribution amplitudes of both particles are, up to QCD corrections, nearly identical. These results are applied to a new calculation of the long-distance charm loop contribution to radiative B → Vγ decays, and it is shown that the approximate symmetry can be exploited to provide an improved theoretical control in the search for New Physics contributions to right-handed currents in radiative decays.

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23

Benelli, Angela. "A test of T and CPT symmetries in the neutral kaon system at the CPLEAR experiment." Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243033.

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24

Gioventù, Alessandra. "Test of lepton flavour universality with charm semileptonic decays." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15749/.

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L'universalità leptonica è una delle simmetrie del Modello Standard (SM). Essa prevede che l'accoppiamento tra i bosoni di gauge e i leptoni delle tre famiglie sia uguale. I recenti risultati sperimentali sulle transizioni b->clnu , in particolare gli osservabili R(D) e R(D*) mostrano una differenza significativa dai valori previsti dal SM, aprendo le porte alla ricerca di nuova fisica anche nei decadimenti di mesoni charmed, che a livello di quark corrispondo alla transizione c->slnu, dove l può essere un muone o un elettrone. I test dello SM sono studiati attraverso la misura del rapporto R(mu/e), definito come R(mu/e)=(dΓ(μ)/dq2)/(dΓ(e)/dq2). In questa tesi è stato realizzato uno studio preliminare che permette la misura di R(mu/e) attraverso la catena di decadimento D*^+ -> (D^0 → K^−l^+nu)pi^+, utilizzando i dati raccolti da LHCb durante il Run-2. Al fine di ottenere le informazioni complete sui prodotti del decadimento D^0 → K^−l^+nu, inclusa la stima del momento del neutrino, è stato implementato un algoritmo di global fit (GF). Inoltre, è stata studiata la contaminazione dello spettro di massa invariante del D^{*+}, dovuta a diversi canali di fondo. Per estrarre il numero di eventi di segnale, è stato fatto un fit di chi-quadro sulla massa invariante del D^{*+}, considerando soltanto il fondo combinatorio su un campione di dati, filtrato con dei tagli di PID, utili a ridurre altri fondi.

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25

Capdevila, Soler Bernat. "Searching for new physics in semileptonic B meson decays." Doctoral thesis, Universitat Autònoma de Barcelona, 2020. http://hdl.handle.net/10803/669491.

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Al llarg dels últims anys, s'han observat nombroses senyals que suggereixen l'existència de Física més enllà del Model Estàndard en desintegracions semi-leptòniques de mesons B, mediades per transicions del tipus b --> sll. Més concretament, l'experiment LHCb, juntament amb altres experiments al LHC i col·laboracions externes com Belle, han trobat desviacions en les mesures experimentals de diferents observables d'important rellevància respecte les seves prediccions teòriques en el Model Estàndard. Parcialment, aquesta situació no es sorprenent, ja que en un conjunt gran de dades un sempre espera tenir un subconjunt en tensió amb les seves prediccions. No obstant, la importància de les observacions actuals és que totes aquestes tensions formen un patró coherent apuntant cap a "una direcció privilegiada". Per aquesta raó, els anàlisis globals d'aquestes dades mostren una discrepància general de més de 5sigmes respecte el Model Estàndard Per estudiar aquestes tensions de manera consistent, treballem des del marc del Hamiltonià efectiu que descriu la dinàmica de les transicions b --> sll. Aquesta descripció, conceptualment senzilla, ens permet descriure qualsevol desintegració d'un mesó B, que procedeixi a través de l'anterior transició, en base a un conjunt reduït de paràmetres. Precisament, aquest fet és el fa possible analitzar la totalitat dels observables on s'observen tensions de manera eficient per mitjà de fits globals. En aquesta Tesi, presentem la última versió dels anàlisis globals esmentats. Primer, descrivim el context teòric general que ens serveix de base per tots els nostres càlculs, fent especial èmfasi en l'estimació dels errors corresponents. I després, exposem els nostres resultats amb tota profunditat de detalls, així com comentem també les seves possibles implicacions.
Recientemente, el campo de las desintegraciones electro-débiles de mesones B ha observado la aparición de numerosas señales que indican la existencia de Física más allá del Modelo Estándar, siendo los procesos mediados por transiciones b --> sll el contexto habitual de dichas señales. Más en detalle, el experimento LHCb, junto con otros de los experimentos en el LHC y otras colaboraciones como Belle, han encontrado desviaciones en los valores experimentales de distintos observables, relevantes en la caracterización de las transiciones b --> sll, con respecto sus predicciones teóricas en el marco del Modelo Estándar. En parte, esta situación no es sorprendente, puesto que uno se espera encontrar varias medidas en tensión con sus predicciones en un conjunto grande de datos. No obstante, lo que es muy destacable es que estas tensiones forman un patrón de desviaciones con coherencia interna y parece que apuntan todas "en la misma dirección". Por esta razón, al evaluar la importancia global del conjunto de tensiones mediante un análisis global, el resultado indica una discrepancia general de los datos con respecto del Modelo Estándar de más de 5sigmas. Para estudiar dichas tensiones de forma consistente utilizamos un Hamiltoniano efectivo, dónde se codifica la dinámica de las transiciones b --> sll. Esta simple herramienta nos permite describir cualquier desintegración de un mesón B, que opere a través de dicha transición, a través de un conjunto reducido de parámetros, hecho que posibilita poder analizar un conjunto numeroso de datos por medio de fits globales. En esta Tesis presentamos la última versión de los citados análisis globales. Primero, describimos el contexto teórico general que sirve de base para todos nuestros cálculos, prestando especial atención a los métodos utilizados para estimar la incertidumbre asociada a nuestras predicciones, para después mostrar todos los detalles de nuestro análisis así como sus implicaciones.
In the recent years, intriguing hints of New Physics (NP) have been accumulated in semileptonic B-meson decays, mostly involving neutral-current transitions b --> sll. The LHCb collaboration, other collaborations at the LHC and the Belle experiment have reported deviations from the Standard Model expectations in several observables measuring the aforementioned transition. These are commonly referred to in the literature as B-anomalies. Not surprisingly, some of these measurements show deviations from the SM predictions by a few standard deviations. More interesting is the fact that several of these deviations from the SM appear to be "in the same direction", in such a way that when quantified by a global fit the discrepancy with the SM is over the 5sigma level. In order to assess the significance of these anomalies and to treat them consistently, we propose a model-independent analysis based on an Effective Hamiltonian encoding the dynamics of the underlying quark level transition. This has the advantage of providing a simple systematic framework where all possible processes, mediated by the same transition, can be described with the same set of parameters, allowing for global fits of large numbers of observables defined in several channels. This Thesis presents our most updated global analyses of b --> sll data. First, we describe the general framework used to compute the different types of observables, paying special attention to the treatment of the uncertainties involved. And then, we discuss both our analytical approach and the implications of the most significant results obtained from our fits.

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26

Wade, Michael Fairbairn. "Semileptonic decays of heavy mesons and the standard model." Thesis, Durham University, 1990. http://etheses.dur.ac.uk/6045/.

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The formalism for a helicity amplitude analysis of the exclusive semileptonic decays of B mesons (B → Dlv and B → D* lv for l = e, µ and r) is introduced. In particular it is shown how measurements of the angular distribution of the subsequent decay D* → Dπ can fully determine the theoretically uncertain hadronic (B → D,D*) matrix elements. A spectator quark based model for the hadronic amplitudes is introduced, and then compared to other existing models and with the presently available experimental data, to extract the quark mixing matrix element |V(_eb)|. The extraction of |V(_ub)|, using exclusive models for b → u decays, is also discussed. The predictions of the free-quark model of inclusive semileptonic B decays are compared with those of the exclusive models, in an attempt to test the reliability of the inclusive model's predictions for |V(_eb)| and |V(_ub)|. A phenomenological analysis of experimental measurements of K(^0) – K(^0) and B(^0) – B(0) mixing is made, incorporating the above determinations of the mixing matrix elements, with a view to constraining the parameters of the standard model, such as the mass of the top-quark.

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27

Gill, James Fenton. "Nonperturbative effects in the semileptonic decays of pseudoscalar mesons." Thesis, University of Edinburgh, 2002. http://hdl.handle.net/1842/14910.

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This thesis describes the calculation of the form factors for four semileptonic decays. The decays considered are those where a pseudoscalar meson composed of a heavy and a light valence quark decays to a vector meson containing only light valence quarks. The form factors were calculated in nonperturbatively O(a) improved quenched lattice QCD. To estimate discretisation effects the calculation was done at b = 6.0 and b = 6.2, with lattice 16³ x 48 and 24³ x 48 respectively. Results are presented for the following semileptonic decays of charmed mesons: D_s (r) ?, D (r) K^* and D (r) ρ. The b = 6.2 and b = 6.0 results agree within errors. The b = 6.2 results were used to calculate integrated decay rates and form factor ratios at q² = 0. The lattice predictions for integrated decay rates are in reasonable agreement with experiment. In some cases the lattice form factor ratios differ significantly from experiment. The simulation results were extrapolated to obtain B (r) ρ form factors at high q². The lattice results and |V_ub| = 3.5 x 10^-3 gives the partially integrated decay rate DG(14 GeV² < q² < q²_max) = 8.7^+1.9_-1.2x 10⁷s^-1 (lattice statistical errors). This is in agreement with the experimental results of the CLEO collaboration. The systematic error associated with the heavy quark extrapolation is estimated to be similar to the statistical error.

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28

Neshatpour, Siavash. "Récentes implications au-delà du modèle standard des désintégrations de mésons beaux." Thesis, Clermont-Ferrand 2, 2013. http://www.theses.fr/2013CLF22354.

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Des progrès expérimentaux importants sont en cours dans l’étude des désintégrations rares de mésons contenant un quark beau et impliquant un quark étrange et une paire de leptons. Le travail présent mesure la portée indirecte de ces progrés sur des extensions supersymétriques du modèle standard. Même dans des modèles contraints, les limites indirectes ainsi obtenues peuvent dans certains cas être plus fortes que celles provenant de la recherche directe de particules supersymétriques. La précision gagnée par les facteurs de forme et les corrections d’ordre supérieur nouvellement implémentés dans le programme public ”SuperIso” montrent alors leur importance
There are fast progresses in the experimental study of rare decay sof mesons containing a b-quark, and involving a pair of leptons and an s-quark. The present work measures the indirect implications of these progresses on the supersymmetric extensions of the Standard Model. Even within constrained models, the indirect limits obtained in this way can in some cases be stronger than those coming from direct searches of supersymmetric particles. The accuracy gained by the form factors and higher order corrections newly implemented in the public code ”SuperIso” are then fully relevant

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29

Oswald, Christian [Verfasser]. "Semileptonic Decays of Strange Beauty Mesons at Belle / Christian Oswald." Bonn : Universitäts- und Landesbibliothek Bonn, 2015. http://d-nb.info/1077290225/34.

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30

Flaecher, Henning Ulrik. "Measurement of hadronic mass moments from semileptonic Î² meson decays." Thesis, Royal Holloway, University of London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.407244.

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31

Atoui, Mariam. "Semileptonic B decays into charmed D( **) mesons from Lattice QCD." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2013. http://tel.archives-ouvertes.fr/tel-00933976.

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Les désintégrations semileptoniques du méson $B$ participent à la détermination de certains paramètres fondamentaux du Modèle Standard. Ce travail décrit essentiellement l'étude des deux canaux de désintégrations $B_s \to D_s \ell \bar\nu_\ell$ et $B\to D^{**} \ell \bar\nu_\ell$ (où les $D^{**}$ sont les premières excitations orbitales des mésons $D$ ayant une parité positive). Le cadre théorique est celui de la QCD sur réseau qui, en discrétisant l'espace-temps, permet de calculer non perturbativement les fonctions de Green de la théorie. En utilisant l'action à masse twistée avec deux saveurs dégénérées de quarks dynamiques ($N_f=2$), nous avons commencé par étudier la spectroscopie des états charmés scalaires $D_0^*$ et tenseurs $D_2^*$. Ensuite, nous avons réalisé la détermination du facteur de forme $\mathscr G_s(1)$ décrivant le processus $B_s\to D_s \ell \bar\nu_\ell$ dans le Modèle Standard. Ce paramètre offre un moyen d'extraire l'élément de la matrice CKM $V_{cb}$. Par ailleurs, et pour la première fois en QCD sur réseau, nous avons déterminé les rapports $F_0(q^2)/F_+(q^2)$ et $F_T(q^2)/F_+(q^2)$ dans la région proche du recul nul: ces contributions sont en effet nécessaires afin de discuter ce canal de désintégration dans certains modèles au-delà du Modèle Standard. Enfin, une étude préliminaire du canal de désintégration $B\to D^{**}$ a été abordée où nous avons trouvé une valeur non nulle de l'élément de matrice décrivant la désintégration $B\to D_0^*$ à recul nul contrairement de ce qui est connu à la limite des quarks lourds. Dans le cas du $B \to D_2^*$, nos résultats ont montré un signal indiquant une différence par rapport aux prédictions de masse infinie. Ces calculs sont indispensables afin de tirer une conclusion plus solide concernant le ''puzzle 1/2 vs 3/2''

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32

Bellerive, Alain. "Investigation of semileptonic B meson decays to p-wave charm mesons." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=34913.

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This thesis presents an investigation of semileptonic B meson decays with a narrow P-wave charm meson in the final state. The data sample consists of 3.29 x 106 BB¯ events collected with the CLEO II detector at the Cornell Electron-positron Storage Ring. The P-wave charm mesons are reconstructed in the chain of decays: D0J→D*+p- ,D*+→D0p+,D 0→K-p+ or D0→K-p+p 0 . Study of the decay B-→D*+p0ℓ -nℓ&d1; reveals useful information about the deficit observed in inclusive charm semileptonic B decays and the effective couplings of the W boson to heavy quark mesons. The results obtained for the exclusive semileptonic product branching fractions are BB-→D0 1ℓ-nℓ &d1;B D01→D*+p - = (0.373 +/- 0.085 +/- 0.052 +/- 0.024)% and BB-→D*0 2ℓ-nℓ&d1; BD*0 2→D*+p- < 0.16% (90% C.L.). The assumption BD01→D* +p- = 67% and BD*02→D *+p- = 20% implies BB-→D01 ℓ-nℓ&d1; (0.56 0.13 +/- 0.08 +/- 0.04)% and BB-→D*0 2ℓnℓ&d1; < 0.8% (90% C.L.). These results indicate that at least 18% of the total B semileptonic rate is still unaccounted for by the observed exclusive decays, B&d1;→D0ℓ- n&d1;ℓ, B&d1;→D*ℓn &d1;ℓ,B&d1; →D1ℓn&d1; ℓ, and B&d1;→D*2 ℓn&d1;ℓ . Furthermore, the first measurement of the q 2 spectrum for B-→D01ℓn &d1;ℓ is presented. The present analysis also suggests that the Λ QCD/mQ corrections beyond the HQS prescriptions might be significant in the theoretical treatment of the dynamics of B semileptonic decays to excited charm mesons.

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33

Bellerive, Alain. "Investigation of semileptonic B meson decays to P-wave charm mesons." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/NQ44361.pdf.

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34

Rusov, Aleksey [Verfasser]. "Hadronic effects and observables in semileptonic B-meson decays / Aleksey Rusov." Siegen : Universitätsbibliothek der Universität Siegen, 2018. http://d-nb.info/1155589424/34.

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35

Schubert, Jens. "Reconstruction of B- --> D*° e- nu Decays and Determination of |Vcb|." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2007. http://nbn-resolving.de/urn:nbn:de:swb:14-1169731847466-67149.

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In this analysis the decay B- --> D*° e- nu is measured. The underlying data sample consists of about 226 million B-meson pairs accumulated on the Y(4S) resonance by the BABAR detector at the asymmetric e+e- collider PEP II. The reconstruction of the decay uses the channels D*° --> D° pi°, D° --> K- pi+ and pi° --> gamma gamma. The neutrino is not reconstructed. Since the rest frame of the B meson is unknown, the boost w of the D*° meson in the B meson rest frame is estimated by w'. The w' spectrum of the data is described in terms of the partial decay width dGamma/dw given by theory and the detector simulation translating each spectrum dGamma/dw into an expectation of the measured w' spectrum. dGamma/dw depends on a form factor F(w) parameterizing the strong interaction in the decay process. To find the best descriptive dGamma/dw a fit to the data determines the following two parameters of dGamma/dw: (i) F(1)|Vcb|, the product between F at zero D*°-recoil and the Quark mixing parameter |Vcb|; (ii) rho^2, a parameter of the form factor F(w). The former parameter scales the height of dGamma/dw and rho^2 varies the shape of it. The determined values of F(1)|Vcb|, rho^2 and the branching fraction BF(B- --> D*° e- nu) are F(1)|Vcb| = (35.8 +- 0.5 +- 1.5) x 10e-03, rho^2 = (1.08 +- 0.05 +- 0.09) and BF(B- --> D*° e- nu) = (5.60 +- 0.08 +- 0.42)%, where the uncertainties are statistical and systematic, respectively. The value of BF(B- --> D*° e- nu) has been determined by an integration of dGamma/dw over the allowed w range using the fitted values of F(1)|Vcb| and rho^2.

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36

Dag, Huseyin. "Investigating The Semileptonic B To K_1(1270,1400) Decays In Qcd Sum Rules." Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611865/index.pdf.

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Quantum Chromodynamics(QCD) is part of the Standard Model(SM) that describes the interaction of fundamental particles. In QCD, due to the fact that strong coupling constant is large at low energies, perturbative approaches do not work. For this reason, non-perturbative approaches have to be used for studying the properties of hadrons. Among several non-perturbative approaches, QCD sum rules is one of the reliable methods which is applied to understand the properties of hadrons and their interactions. In this thesis, the semileptonic rare decays of $B$ meson to $K_{1}(1270)$ and $K_{1} (1400)$ are analyzed in the framework of three point QCD sum rules approach. The $Brightarrow K_{1} (1270,1400) ell^+ ell^-$ decays are significant flavor changing neutral current (FCNC) decays of the $B$ meson, since FCNC processes are forbidden at tree level at SM. These decays are sensitive to the new physics beyond SM. The radiative $Brightarrow K_{1}(1270) gamma$ decay is observed experimentally. Although semileptonic $Bto K_1(1270,1400)$ decays are still not observed, they are expected to be observed at future B factories. These decays happens at the quark level with $brightarrow s ell^+ ell^- $ transition, providing new opportunities for calculating CKM matrix elements: $V_{tb}$ and $V_{ts}$. Applying three point QCD sum rules to $Brightarrow K_{1} (1270,1400) ell^+ ell^-$ decays is tricky, due to the fact that the $K_{1} (1270)$ and $K_{1} (1400)$ states are the mixtures of ideal $^{3}P_{1}(K_{1}^{A})$ and $^{1}P_{1}(K_{1}^{B})$ orbital angular momentum states. First, by taking axial vector and tensor current definitions for $K_1$ mesons, the transition form factors of $Brightarrow K_{1A} ell^+ ell^-$ and $Brightarrow K_{1B} ell^+ ell^-$ are calculated. Then using the definitions for $K_1$ mixing, the transition form factors of $Brightarrow K_{1} (1270,1400) ell^+ ell^-$ decays are obtained. The results of these form factors are used to estimate the branching ratio of $B$ meson into $K_1(1270)$ and $K_1(1400)$. The results obtained for form factors and branching fractions are also compared with the ones in the literature.

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37

King, James Edward. "A study of charm meson production in semileptonic B decays at LEP." Thesis, Queen Mary, University of London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339003.

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38

Donald, Gordon. "Semileptonic and radiative meson decays from lattice QCD with improved staggered fermions." Thesis, University of Glasgow, 2013. http://theses.gla.ac.uk/4325/.

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Improved staggered fermions are a numerically efficient formulation of the fermion action in lattice QCD. They are used for nonperturbative theoretical calculations of the QCD form factors appearing in the decay rates for radiative and semileptonic meson transitions. The constituent quarks are bound inside hadrons by the strong interaction, so the decay rate depends on the interactions between the quarks, which are described by QCD. The fermion action used in these calculations is the Highly Improved Staggered Quark (HISQ) action. The HISQ Dirac operator, $\slashed{D}_{HISQ}$, contains four tastes of quark equivalent to one continuum quark, which is a consequence of the discretisation. In gauge configurations including staggered sea quarks, the extra tastes are accounted for by taking the fourth root of the fermion determinant. The validity of this step relies on the taste structure of $\slashed{D}_{HISQ}$. To look into this, the interactions of the eigenvectors of $\slashed{D}_{HISQ}$ with the topology of the gauge field is studied. The results show that the eigenvectors corresponding to the different tastes decouple in the continuum limit in such a way that $\slashed{D}_{HISQ}$ resembles the continuum Dirac operator. Using the HISQ action for the charm quark, the form factor $V(q^2)$ appearing in the radiative decay rate for $J/\psi \to \eta_c \gamma$ is calculated. The form factor on the lattice is calculated by computing 3-point correlation functions, which are fitted simultaneously with 2-point correlation functions to obtain the meson transition matrix element. Only the form factor at $q^2 = 0$ enters the decay rate for a physical photon, so the kinematics of the decay are tuned to calculate $V(0)$. The lattice operator used for the electromagnetic vector current is nonperturbatively normalised. Lattice QCD can also be used to calculate matrix elements for the decays of mesons to 2 photons. The form factor for the radiative decay $\eta_c \to 2\gamma$ is calculated at the physical kinematics using nonperturbatively normalised lattice operators for the currents. The form factor is the same when calculated on gauge configurations containing $N_f = 2+1$ flavours of asqtad sea quarks and $N_f = 2+1+1$ flavours of HISQ sea quarks. Lattice 3-point correlators are used to calculate the form factors for the semileptonic decay $D_s \to \phi \ell \nu$. This interaction is mediated by a weak $W$ boson, so contains vector and axial vector form factors. Each of these is calculated on the lattice with a nonperturbatively normalised current. The decay includes a $c \to s$ quark decay, so the experimentally measured decay rate depends on the CKM matrix element $V_{cs}$. By comparing the theoretical calculation of the decay rate to the measurements, a value of $V_{cs} = 0.975(48)$ is obtained.

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39

Corwin, Luke Andrew. "Leptonic Decays of the Charged B Meson." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1228320450.

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40

Schubert, Jens. "Reconstruction of B- --> D*° e- nu Decays and Determination of |Vcb|." Doctoral thesis, Technische Universität Dresden, 2006. https://tud.qucosa.de/id/qucosa%3A25025.

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In this analysis the decay B- --> D*° e- nu is measured. The underlying data sample consists of about 226 million B-meson pairs accumulated on the Y(4S) resonance by the BABAR detector at the asymmetric e+e- collider PEP II. The reconstruction of the decay uses the channels D*° --> D° pi°, D° --> K- pi+ and pi° --> gamma gamma. The neutrino is not reconstructed. Since the rest frame of the B meson is unknown, the boost w of the D*° meson in the B meson rest frame is estimated by w'. The w' spectrum of the data is described in terms of the partial decay width dGamma/dw given by theory and the detector simulation translating each spectrum dGamma/dw into an expectation of the measured w' spectrum. dGamma/dw depends on a form factor F(w) parameterizing the strong interaction in the decay process. To find the best descriptive dGamma/dw a fit to the data determines the following two parameters of dGamma/dw: (i) F(1)|Vcb|, the product between F at zero D*°-recoil and the Quark mixing parameter |Vcb|; (ii) rho^2, a parameter of the form factor F(w). The former parameter scales the height of dGamma/dw and rho^2 varies the shape of it. The determined values of F(1)|Vcb|, rho^2 and the branching fraction BF(B- --> D*° e- nu) are F(1)|Vcb| = (35.8 +- 0.5 +- 1.5) x 10e-03, rho^2 = (1.08 +- 0.05 +- 0.09) and BF(B- --> D*° e- nu) = (5.60 +- 0.08 +- 0.42)%, where the uncertainties are statistical and systematic, respectively. The value of BF(B- --> D*° e- nu) has been determined by an integration of dGamma/dw over the allowed w range using the fitted values of F(1)|Vcb| and rho^2.

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41

Phipps, Martin. "A partonic treatment of the inclusive and exclusive semileptonic decays of heavy mesons." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40425.

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In this thesis, the semileptonic decays of heavy mesons are treated using fully relativistic kinematics. By means of an effective vertex, the effects of Fermi momentum are included both at the inclusive and at the exclusive levels, and the spins of both parent and daughter particles are taken into account. The differential decay rates with respect to the lepton energy and momentum transfer are compared with data from ARGUS and CLEO. This approach is superior to both the ACCMM and ISGW models in that it enables us to precisely calculate CKM matrix elements and decay constants in addition to the inclusive and exclusive rates. From the inclusive data, we both conclude that $ rm {v sb{ub} over V sb{cb}} = .07 pm .05$ and estimate the magnitudes of the matrix elements themselves to be $ rm vert V sb{ub} vert = .038 pm .004$ and $ rm vert V sb{cb} vert = .003 pm .002$. Of particular interest is the fact this model predicts that the exclusive decays $B to Dl sbsp{ mu}{-}$ and $B to D sp*l sbsp{ mu}{-}$ together only account for about 60% of the total rate and thus agrees with data that suggests that as much as 40% of the total B semileptonic decay occurs through other channels. The B and D decay constants are, meanwhile, estimated to be $f sb{B}$ = f$ sb{D} approx 0.4$ GeV. After taking the heavy quark limit we also obtain $ rho sp2 = .9 pm .4$.

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42

Thorn, Stephen Andrew. "Observation of semileptonic charmless bottom meson decays with the aleph detector at LEP." Thesis, University of Glasgow, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264082.

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43

Tripathi, Arun K. "Search for neutral D meson - neutral anti D meson mixing using semileptonic decays /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu148794532076064.

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44

Luzio, Marco Aurelio. "Study of analytical methods for electron track detection from heavy quark decays generated by sqrt(s)=8TeV pp collisions at ALICE." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-07062017-140205/.

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A study of the usage of ALICEs time of flight (TOF), time projection chamber (TPC), and electromagnetic calorimeter (EMCal), aiming at detecting and separating electrons and positrons (e±) originated from different sources, was carried out. To accomplish the objectives of the research, data gathered from the 2012 proton-proton (pp) collision experiment were used. At a center of mass energy of sqrt(s)=8TeV, the collision of the proton beams liberates heavy quarks, charm and bottom, with approximate lifetimes of approximately 10^13s and 10^12s, respectively. The e± generated through weak semileptonic heavy flavor decays are of interest for studying quarks, therefore it served solely as motivation and incentive for the research carried out and described herein. The introduction of carefully selected cuts, with the purpose of separating partial data collected in the three detectors, permitted the understanding of their effect on the results. Furthermore, due to the fact that the TOFs design was not meant to separate e± from the other heavier particles, only the general effects of introducing a simple cut in the beta=v/c values were analyzed. The more specific cuts were only used for the data generated by the events detected by the TPC and the EMCal. A combination of cuts based on the particles energy loss as a function of traveled distance (dE/dx), with the ratio of energy to momentum (E/p) of the particle, was adopted to enable the separation process, thus allowing for the isolation of e± from the other particles, namely pi±, K±, and p/p. The analysis was performed for values of total particle momentum in the range 0<=p<=6GeV/c. A comparison of the raw data with the results obtained by applying this procedure, indicated a substantial increase in the e± yield and efficiency, reaching average values above 90% over the entire momentum range.
Um estudo do uso dos detetores de tempo de voo (TDV), câmara de projeção de tempo (CPT), e calorímetro eletromagnético (CalEM) do ALICE, visando detectar elétrons e pósitrons (e±) originados por diferentes fontes, foi realizado. Para atingir os objetivos da pesquisa, dados coletados durante o experimento de colisões próton-próton em 2012 foram utilizados. Com um nível de enegia do centro de mass igual a raiz(s)=8TeV, a colisão dos feixes de prótons libera quarks pesados, charm e bottom, com tempo de vida de aproximadamente 10^13s e 10^12s, respectivamente. Os e± gerados pelo decaimento fraco semileptônico de sabores pesados é de interesse para o estudo dos quarks, portanto, o conceito serviu somente como motivação e incentivo para a pesquisa realizada e descrita nesta dissertação. A introdução de cortes específicos, com a finalidade de parcialmente separar dados coletados nos três detectores, permitiu adquirir entendimento sobre os efeitos do cortes nos resultados. Adicionalmente, em virtude do projeto do TDV não ter sido feito visando separar e± oriundos do decaimento dos sabores pesados das demais partículas mais massivas, somente os efeitos gerais de introduzir um corte simples nos valores de beta=v/c, foram analisados. Os cortes mais específicos foram somente nos dados detectados pelo CPT e pelo CalEM. Uma combinação de cortes baseados na perda de energia da partícula em função da distância percorrida (dE/dx), com a razão entre a energia e o momento da partícula (E/p), foi adotada para viabilizar o processo de separação, desta forma permitindo a separação dos e± das demais partículas, ou seja, dos pi±, K±, and p/p. A análise foi realizada para valores de momento total das partículas na faixa 0<=p<=6GeV/c. Uma comparação dos dados originais com os resultados obtidos pela aplicação do procedimento, indicou um aumento substancial do rendimento e eficiência dos e±, atingindo valores médios acima de 90% na faixa inteira de momento.

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45

Salerno, Gianluigi. "Theory of semileptonic B → D(∗)lν decays and sensitivity studies to new physics effects." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20586/.

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In questa tesi, si vuole investigare l’effetto che la fisica oltre il modello standard ha sui decadimenti semileptonici B → D(∗)lν, dove l può essere un τ, un µ o un elettrone. Questo lavoro è stato spronato dalle cosiddette anomalie della fisica del B in processi a corrente carica, che consistono in un tasso del decadimento B → D(∗)τν più alto rispetto alle predizioni teoriche. Tra i vari tipi di fisica oltre lo standard model introdotti per spiegare questa ed altre anomalie del B, la soluzione con un contributo di tipo tensoriale appare la più convincente e studiata nella letteratura recente, principalmente per la sua generalità e semplicità. Altri tipi di contributi, come i leptoquarks e il modello a due Higgs, vengono considerati. Per studiare questi effetti, la tesi è stata organizzata in due parti: una teorica ed una sperimentale. Nella prima, dopo una introduzione sulle recenti osservazioni sperimentali che hanno evidenziato queste anomalie, vengono presentate le conoscenze teoriche necessarie per affrontare l’argomento. Sono quindi spiegati i fattori di forma, che sono cruciali per descrivere i decadimenti semileptonici, e viene considerata la loro importanza per fare predizioni affidabili. Si deriva in dettaglio l’ampiezza di decadimento sia per il caso B → D sia per il B → D∗, mostrando come costruire osservabili sensibili al contributo di nuova fisica. Ignorando gli effetti del rivelatore nella ricostruzione dei decadimenti, si attua uno studio sulla sensibilità ai fattori di forma e alla fisica oltre lo standard model. Dopo aver introdotto i metodi Monte Carlo, si descrive l’approccio usato per effettuare lo studio di fattibilità sia per il caso di solo modello standard, sia per il caso di nuova fisica. Inﬁne, vengono mostrati i risultati dello studio, e vengono presentate le conclusioni e prospettive future riguardo questa area di ricerca

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46

Villa, Andrea. "Measurement of y_CP with D^0 mesons from semileptonic B-meson decays at LHCb." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/21249/.

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This thesis reports a measurement of the charm-mixing observable yCP using D^0->K^+K^−, D^0->pi^+pi^−, and D^0->K^−pi^+ decays, where the D^0 meson originates from semileptonic B-meson decays. The analysis is performed on the full Run 2 dataset collected by LHCb with pp collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.57 fb^−1 . The dataset is divided into 18 exclusive D^0 decay-time bins, in which an invariant mass fit is performed to extract the signal yield for each decay channel. The ratios of KK/Kpi and pipi/Kpi yields in each bin, corrected for the efficiency as function of the decay-time estimated from a Monte Carlo sample, are then fitted to extract the difference between the decay widths of KK (pipi) and Kpi channels, ∆Γ^{KK} (∆Γ^{pipi}). Finally, y_CP is computed as ∆Γt(D^0), where t(D^0) is the precisely known D^0 lifetime. The values obtained from the two decay channels with preliminary systematic uncertainties are y_CP^{KK} = (75.98 ± 0.07 (stat) ± 0.06 (syst))%, y_CP^{pipi} = (76.29 ± 0.14 (stat) ± 0.05 (syst))%, which are consistent with each other (the central values are blind), and when combined yield a result of y_CP = (76.08 ± 0.06 (stat) ± 0.04 (syst))%. The analysis aims at updating the previous LHCb measurement with a larger data sample size, and is expected to improve the precision by a factor two with respect to the current world average y_CP = (0.715 ± 0.111)%.

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47

Nobes, Matthew A. "Semileptonic decays of the B[subscript]c meson in the quark meson effective theory." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0027/MQ51434.pdf.

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48

Janicek, René. "Search for charmed meson-pion continuum production in semileptonic B decays at CLEO II." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ64583.pdf.

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49

Forbes, Kevin Andrew John. "A study of semileptonic decays of heavy quarks using the DELPHI detector at LEP." Thesis, University of Liverpool, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240275.

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50

Eygi, Zeynep Deniz. "The Standard Model Analyasis Of The Cp Violation In The Inclusive Semileptonic B-meson Decays." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12604712/index.pdf.

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Abstract:

Being a flavor changing neutral current process, inclusive semileptonic B- meson decays provide reliable testing grounds for the Standard Model at the loop level. They are also importanat in the CKM phenomology and investing the CP violation due to the existence of sizable interference terms in the decay amplitude. In this work , the rare inclusive semileptonic B- meson decays for (lepton is electron ,muon , tau) are investigated in the context of the Standard Model.The differential branching ratio, forward-backward asymmetry ,CP &ndash
violating asymmetry and CP &ndash
violating asymmetry in the forward-backward asymmetry in these processes are examined.The dependencies of these physical parameters on the Standard Model parametres are analyzed by paying a special attention to the long distance effects. Although the branching ratios predicted for the inclusive semileptonic B- meson decays are relatively small because of CKM suppression , it has been found that there is a significant ACP and ACP(AFB) for these processes.

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Dissertations / Theses on the topic 'Semileptonic decay'

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