This thesis presents an analysis of inclusive semileptonic $B \to X_u e \nu$ decays using approximately 454 million $\Upsilon(4S) \to B \bar{B}$ decays collected during the years 1999 to 2008 with the BABAR detector. The electron energy, $E_e$, and the invariant mass squared of the electron-neutrino pair,$ q^2$, are reconstructed, where the neutrino kinematics is deduced from the decay products of both B mesons. The final hadronic state,$ X_u$, consists of a sum of many hadronic channels, each of which contains at least one $u$ quark. The variables $q^2$ and $E_e$ are then combined to compute the maximum kinematically allowed invariant mass squared of the hadronic system, $s_h^{max}$. Using these kinematic quantities, the partial branching fraction, $\Delta BR(B \to X_u e \nu)$, unfolded for detector effects, is measured to be $\Delta BR(E_e>2.0 GeV, s_h^{max}<3.52 GeV^2) = (3.33 \pm 0.18 \pm 0.21) \times 10^{-4} in the $\Upsilon(4S)$ and \Delta \tilde{\BR}(\tilde E_e>1.9 GeV, \tilde {s}^{max}_{h} < 3.5 GeV^2) = (4.57 \pm 0.24 \pm 0.32) \times 10^{-4} in the $B$ meson rest frames. The quoted errors are statistical and systematic, respectively. The CKM matrix element $|V_{ub}|$ is determined from the measured $\Delta \tilde{\BR}$ using theoretical calculation based on Heavy Quark Expansion. The result is $|V_{ub}| = (4.19 \pm 0.18{}^{+0.26}_{-0.20} {}^{+0.26}_{-0.25}) \times 10^{-3}, where the errors represent experimental uncertainties, uncertainties from HQE parameters and theoretical uncertainties, respectively.

In dieser Arbeit werden die seltenen Zerfälle b -> s gamma und b -> s g, sowie die BB¯-Oszillation einschließlich QCD-Korrekturen in Next-to-Leading-Log-Approximation untersucht. Es handelt sich hierbei um Flavor Changing Neutral Current (FCNC) Prozesse, welche auf dem Born-Niveau innerhalb des Standardmodells verboten sind. Diese Prozesse sind besonders geeignet zum Testen des Standardmodells, da mögliche Erweiterungen potentiell denselben Beitrag liefern können. Als Erweiterungen werden das 2-Higgs-Dublett-Modell, Links-Rechts-Modelle und insbesondere das Minimale Supersymmetrische Standardmodell diskutiert. Am Beispiel der BB¯-Oszillation wird gezeigt, daß die Bestimmung der Wilson-Koeffizienten inabhängig von der Behandlung der leichten Felder ist. Dazu wird zum einen die dimensionale Regularisierung der IR-Divergenzen und zum anderen die Einführung von IR-Regulatoren benutzt. Für das BB¯-Mixing werden mit Hilfe der sehr genau gemessenen Massenaufspaltung "Delta m B" Aussagen zu (V td V* tb)² getroffen. Weiterhin wird das Verzweigungsverhältnis BR[B -> "X s gamma"] im Standardmodell und im Minimalen Supersymmetrischen Standardmodell bestimmt. / Calculations for the rare decays b -> s gamma and b -> s g, as well as the BB¯-mixing inclusive QCD-corrections in Next-to-Leading-Log-Approximation are presented throughout this work. The decays and the mixing are caused by Flavor Changing Neutral Current (FCNC) processes, which are absent on the tree-level within the framework of the Standard-Model. Hence these processes are qualified to test the validity of the Standard-Model, because possible extensions may provide similar contributions. Considered extensions are the 2-Higgs-Doublet-Model, Left-Right-Models and the Minimal Supersymmetric Standard-Model. It is shown that the determination of the Wilson-coefficients is independent of the treatmentof the light fields for the case of the BB¯-mixing. For this proof the dimensional regularisation of the IR-divergences on one side and a regulator mass for the light fields on the other side isutilized. The well-known value for the mass splitting "Delta m B" available from the BB¯-oscillation is applied to deduce (V td V* tb)². Furthermore the branching ratio BR[B -> "X s gamma"] is calculated within the Standard-Model and the Supersymmetric Standard-Model.

Title: Study of b-quark processes in the Belle experiment Author: Daniel Červenkov Department: Institute of Particle and Nuclear Physics Supervisor: Zdeněk Doležal Co-Supervisor: Karim Trabelsi Abstract: A study regarding the plausability of using the B0 → D∗ ρ± decay channel and the data set of the Belle experiment to measure sin(2φ1+φ3) has been carried out. Two fitters have been created. A time-independent one, which ex- hibits high stability and reports gratifying fit uncertainties, and a time-dependent one. During the testing of the latter we have discovered an EvtGen flaw and pro- posed a temporary workaround. Nevertheless, the time-dependent fitter fails to recover the correct values. More work will be needed to reach conclusive results. Keywords: B meson, CP violation, angular analysis, time-dependent, fitter

We use a global fit to determine the form factor slopes and branching fractions of the decays B --> Dlnu and B --> D*lnu. We reconstruct Dl pairs and construct a 3-dimensional distribution binned in lepton momentum, D momentum and cosTheta(B-Dl). These kinematic variables provide good separation between the signal and background. We fit electron and muon samples separately and combine them after calculating systematic uncertainties. The form factor slopes, rhoD^2 for B --> Dlnu and rho^2 for B --> D*lnu decays, are measured to be rhoD^2 = 1.22 +- 0.04 +- 0.07 and rho^2 = 1.21 +- 0.02 +- 0.07, where the errors are statistical and systematic, respectively. Branching fractions are fitted to be B(B+ --> D0lnu) = (2.36 +- 0.03 +- 0.12) % and B(B^+ --> D*0lnu) = (5.37 +- 0.02 +- 0.21) %. We use these results to determine the products, G(1)|Vcb| = (43.8 +- 0.8 +- 2.3)*10^{-3} and F(1)|Vcb| = (35.7 +- 0.2 +- 1.2)*10^{-3} of the form factors at zero recoil and the CKM matrix element |Vcb|, from which |Vcb| can be extracted using theoretical input.

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.

Using the general, model indepenent form of the effective Hamiltonian, the general expressions of the longitudinal, normal and transversal polarization asymmetries for l+ and l- for the effective B -&gt / K(K*)l+l- decays has been calculated. Existence of regions of Wilson coefficients for which the branching ratio coincides with the Standard Model result, while the lepton polarizations differ from the standard model prediction is expected. Hence, studying lepton polarizations in these regions of Wilson coefficients may be helpful in establishing new physics beyond standard model.

We use a global fit to determine the form factor slopes and branching fractions of the decays B --> Dlnu and B --> D*lnu. We reconstruct Dl pairs and construct a 3-dimensional distribution binned in lepton momentum, D momentum and cosTheta(B-Dl). These kinematic variables provide good separation between the signal and background. We fit electron and muon samples separately and combine them after calculating systematic uncertainties. The form factor slopes, rhoD^2 for B --> Dlnu and rho^2 for B --> D*lnu decays, are measured to be rhoD^2 = 1.22 +- 0.04 +- 0.07 and rho^2 = 1.21 +- 0.02 +- 0.07, where the errors are statistical and systematic, respectively. Branching fractions are fitted to be B(B+ --> D0lnu) = (2.36 +- 0.03 +- 0.12) % and B(B^+ --> D*0lnu) = (5.37 +- 0.02 +- 0.21) %. We use these results to determine the products, G(1)|Vcb| = (43.8 +- 0.8 +- 2.3)*10^{-3} and F(1)|Vcb| = (35.7 +- 0.2 +- 1.2)*10^{-3} of the form factors at zero recoil and the CKM matrix element |Vcb|, from which |Vcb| can be extracted using theoretical input.

This thesis presents an analysis of inclusive semileptonic $B \to X_u e \nu$ decays using approximately 454 million $\Upsilon(4S) \to B \bar{B}$ decays collected during the years 1999 to 2008 with the BABAR detector. The electron energy, $E_e$, and the invariant mass squared of the electron-neutrino pair,$ q^2$, are reconstructed, where the neutrino kinematics is deduced from the decay products of both B mesons. The final hadronic state,$ X_u$, consists of a sum of many hadronic channels, each of which contains at least one $u$ quark. The variables $q^2$ and $E_e$ are then combined to compute the maximum kinematically allowed invariant mass squared of the hadronic system, $s_h^{max}$. Using these kinematic quantities, the partial branching fraction, $\Delta BR(B \to X_u e \nu)$, unfolded for detector effects, is measured to be $\Delta BR(E_e>2.0 GeV, s_h^{max}<3.52 GeV^2) = (3.33 \pm 0.18 \pm 0.21) \times 10^{-4} in the $\Upsilon(4S)$ and \Delta \tilde{\BR}(\tilde E_e>1.9 GeV, \tilde {s}^{max}_{h} < 3.5 GeV^2) = (4.57 \pm 0.24 \pm 0.32) \times 10^{-4} in the $B$ meson rest frames. The quoted errors are statistical and systematic, respectively. The CKM matrix element $|V_{ub}|$ is determined from the measured $\Delta \tilde{\BR}$ using theoretical calculation based on Heavy Quark Expansion. The result is $|V_{ub}| = (4.19 \pm 0.18{}^{+0.26}_{-0.20} {}^{+0.26}_{-0.25}) \times 10^{-3}, where the errors represent experimental uncertainties, uncertainties from HQE parameters and theoretical uncertainties, respectively.

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.

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.