Techn. University, Diss., 2002--Dresden.

Techn. Hochsch., Diss., 2005--Aachen.

In the thesis we study the decay of B0 meson to D∗ s and ρ mesons. The thesis explains the methods and approaches to data analysis in so-called B-factories, simmilar to the KEKB accelerator. The aim of this thesis is to calculate the branching fraction of this decay to further improve the previously measured branching ratio at BaBar experiment with additional data gained from an ex- periment with higher integrated luminosity. This thesis's prospect is not only broadening our knowledge of branching fractions of B0 meson decays, but also it is a starting point for further analysis with the goal of broadening our knowl- edge of CP symmetry violation in the Standard Model by measuring angles of the Unitary Triangle. 1

No description available.

BABAR is a particle physics experiment at the Stanford Linear Accelerator Center (SLAC). The purpose of BABAR is to study matter-antimatter asymmetry in the bottom quark system. At SLAC, electons and positrons collide, which annihilate and decay into a variety of daughters. An Upsilon(4S) meson is one of the possible daughters. An Upsilon(4S) decays into a B meson and an anti-B meson more than 96% of the time. A B meson has an anti-bottom quark and an anti-B meson has a bottom quark. The purpose of this thesis is to measure how many Upsilon(1S) originated from Upsilon(4S) in the entire BABAR data set. This thesis compares on-peak data and off-peak data. On-peak data was taken at center of mass energy 10.58GeV. One of the possible interactions is e+e− -> Upsilon(4S) since the mass of Upsilon(4S) is 10.58GeV/c^2. On-peak data, taken at center of mass energy 10.54GeV, is not enough to have any BB pairs because 10.54GeV is less than the mass of an Upsilon(4S). This thesis can be useful for BABAR physicist because it helps set an upper limit on how many BB pairs there are in the entire BABAR data set. In other words, it sets an upper limit on how much more than 96% does Upsilon(4S) decay to BB. Measurement of the decay of Upsilon(4S) -> Upsilon(1S) + X give evidence for non-BB decays of the Upsilon(4S). The final results of this study show that there were (110 +- 3) × 10^5 Upsilon(1S) on-peak, of which (10 +- 9) × 10^5 originated from an Upsilon(4S). Increasing the centre of mass energy from 10.54GeV to 10.58GeV increases the Upsilon(1S) production by (10 +- 8)%.

This thesis presents first measurements of moments of the hadronic n_X^2 distribution measured in inclusive semileptonic decays of B mesons to final states containing a charm quark, B->Xc l nu. The variable n_X^2 is a combination of the invariant mass of the charmed meson m_X, its energy in the B-meson rest-frame E_X, and a constant \tilde{\Lambda} = 0.65 GeV, n_X^2 = m_X^2 c^4 - 2 \tilde{\Lambda} E_X + \tilde{\Lambda}^2. The moments <n_X^k> with k=2,4,6 are measured as proposed by theory to constrain assumptions made in the theoretical description of inclusive observables in semileptonic B-meson decays. This description uses Heavy Quark Expansion (HQE), an effective QCD combined with an Operator Product Expansion. The measurement is based on a sample of 231.6 million e+e- -> Y(4S) -> B\bar{B} events recorded with the BABAR experiment at the PEP-II e+e--storage rings at SLAC. We reconstruct the semileptonic decay by identifying a charged lepton in events tagged by a fully reconstructed hadronic decay of the second B meson. Correction procedures are derived from Monte Carlo simulations to ensure an unbiased measurement of the moments of the n_X^2 distribution. All moments are measured requiring minimum lepton momenta between 0.8 GeV/c and 1.9 GeV/c in the rest frame of the B meson. Performing a simultaneous fit to the measured moments <n_X^k> up to order k=6 combined with other measurements of moments of the lepton-energy spectrum in decays B->Xc l nu and moments of the photon-energy spectrum in decays B->Xs gamma, we determine the quark-mixing parameter |V_{cb}|, the bottom and charm quark masses, the semileptonic branching fraction BR(B->X l nu), and four non-perturbative heavy quark parameters. Using HQE calculations in the kinetic scheme up to order 1/m_b^3 we find |V_{cb}| = (41.65 +- 0.43 +- 0.40 +- 0.58) x 10^{-3} and m_b = (4.570 \pm 0.033 \pm 0.043)GeV/c^2, where the first uncertainty refers to experimental contributions, the second to uncertainties in the HQE, and the third to theoretical uncertainties in the calculations of the semileptonic decay rate. All obtained results are consistent with previous determinations. The inclusion of the moments <n_X^6> decreases the uncertainty on the HQE parameters mu_{pi} and rho_{D}. Furthermore, the theoretical treatment of higher order corrections in the HQE used for the moments <m_X^k> has been verified with these new measurements.

This thesis presents first measurements of moments of the hadronic n_X^2 distribution measured in inclusive semileptonic decays of B mesons to final states containing a charm quark, B->Xc l nu. The variable n_X^2 is a combination of the invariant mass of the charmed meson m_X, its energy in the B-meson rest-frame E_X, and a constant \tilde{\Lambda} = 0.65 GeV, n_X^2 = m_X^2 c^4 - 2 \tilde{\Lambda} E_X + \tilde{\Lambda}^2. The moments <n_X^k> with k=2,4,6 are measured as proposed by theory to constrain assumptions made in the theoretical description of inclusive observables in semileptonic B-meson decays. This description uses Heavy Quark Expansion (HQE), an effective QCD combined with an Operator Product Expansion. The measurement is based on a sample of 231.6 million e+e- -> Y(4S) -> B\bar{B} events recorded with the BABAR experiment at the PEP-II e+e--storage rings at SLAC. We reconstruct the semileptonic decay by identifying a charged lepton in events tagged by a fully reconstructed hadronic decay of the second B meson. Correction procedures are derived from Monte Carlo simulations to ensure an unbiased measurement of the moments of the n_X^2 distribution. All moments are measured requiring minimum lepton momenta between 0.8 GeV/c and 1.9 GeV/c in the rest frame of the B meson. Performing a simultaneous fit to the measured moments <n_X^k> up to order k=6 combined with other measurements of moments of the lepton-energy spectrum in decays B->Xc l nu and moments of the photon-energy spectrum in decays B->Xs gamma, we determine the quark-mixing parameter |V_{cb}|, the bottom and charm quark masses, the semileptonic branching fraction BR(B->X l nu), and four non-perturbative heavy quark parameters. Using HQE calculations in the kinetic scheme up to order 1/m_b^3 we find |V_{cb}| = (41.65 +- 0.43 +- 0.40 +- 0.58) x 10^{-3} and m_b = (4.570 \pm 0.033 \pm 0.043)GeV/c^2, where the first uncertainty refers to experimental contributions, the second to uncertainties in the HQE, and the third to theoretical uncertainties in the calculations of the semileptonic decay rate. All obtained results are consistent with previous determinations. The inclusion of the moments <n_X^6> decreases the uncertainty on the HQE parameters mu_{pi} and rho_{D}. Furthermore, the theoretical treatment of higher order corrections in the HQE used for the moments <m_X^k> has been verified with these new measurements.

LHCb is an experiment designed to make precision measurements of Charge- Parity violation in the B meson system. We report a measurement of the B± crosssection and production asymmetry, using B± → J/u K± decays collected at the LHCb detector in 2010 and 2011. Using 27.6 pb-1 of pp collisions at a centre-of-mass energy 7 TeV, we obtain a B± cross-section of [41.6 ± 0.6 (stat.) ± 3.0 (sys.) ± 4.2 (lumi.)] μb in the rapidity region 2 to 4.5. Using 371.1 pb-1 of pp collisions at a centre-of-mass energy 7 TeV, we obtain a B± production asymmetry of [-2.09 ± 1.20 ± 0.8 (CP) ]% in the same rapidity region. The Ring Imaging Cherenkov system of LHCb uses Hybrid photon detectors (HPDs) for single photon detection. This thesis summarises the use of ion feedback measurements as indicators of HPD vacuum quality.

Results of the search for the rare decay $B_s^0 \to \mu^+ \mu^-$ using data collected by the D0 detector at the Fermilab Tevatron collider are presented. This analysis covers the full Run II data set, corresponding to approximately 10.4~fb$^{-1}$ of integrated luminosity in $p\bar{p}$ collisions at a center of mass energy of 1.96 TeV. The analysis used new variables and a multivariate technique to improve the background reduction. After seeing fewer events than expected from background, a new Tevatron best observed limit was set on the branching fraction of the decay at $\cal{B}$($B_s^0 \to \mu^+ \mu^-$) $< 15 \times 10^{-9}$ ($12 \times 10^{-9}$) at the 95\% (90\%) C.L.

In dieser Arbeit werden die seltenen Zerfälle b -&amp;gt; s gamma und b -&amp;gt; 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 &amp;quot;Delta m B&amp;quot; Aussagen zu (V td V* tb)² getroffen. Weiterhin wird das Verzweigungsverhältnis BR[B -&amp;gt; &amp;quot;X s gamma&amp;quot;] im Standardmodell und im Minimalen Supersymmetrischen Standardmodell bestimmt. / Calculations for the rare decays b -&amp;gt; s gamma and b -&amp;gt; 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 &amp;quot;Delta m B&amp;quot; available from the BB¯-oscillation is applied to deduce (V td V* tb)². Furthermore the branching ratio BR[B -&amp;gt; &amp;quot;X s gamma&amp;quot;] is calculated within the Standard-Model and the Supersymmetric Standard-Model.