This thesis reports an analysis of 3.0fb^-1 of pp collision data collected by the LHCb experiment in 2011 and 2012. Decays of neutral B mesons to neutral D mesons and excited neutral kaons are reconstructed, because of their sensitivity to the CP-violating phase of the CKM matrix, γ.

Two measurements of the Cabibbo-Kobayashi-Maskawa angle &gamma; using B &rarr; DK and B⁰ &rarr; DK^&ast;0 decays are presented in this thesis. The subsequent D meson decays to the K_S⁰&pi;⁺&pi;^− and K_S⁰K⁺K^− final states are studied using a binned Dalitz plot analysis. The D strong-phase variation over the Dalitz plot is taken from measurements performed at the CLEO-c experiment, making the analysis independent of a model to describe the D decay amplitude. Both measurements are performed using proton-proton collision data collected by the Large Hadron Collider beauty (LHCb) experiment in 2011 and 2012, corresponding to an integrated luminosity of 3 fb^−1 at centre-of-mass energies &radic;s = 7 TeV and 8 TeV. The value &gamma;= (62 ⁺¹⁵<sub style='position: relative; left: -1.7em;'>−14</sub>)° is measured using B⁰ &rarr; DK^&ast;0 decays and &gamma; = (71 ± 20)° is measured using B⁰ &rarr; DK^&ast;0 decays, with a second solution for each value corresponding to &gamma; + 180°. The measurements are consistent with the world average value of &gamma;.

Dans cette thèse nous présentons des études sur les mésons B effectués en utilisant les données enregistrées par l'expérience Babar auprès de PEP-II à SLAC. D'abord nous présentons la recherche des désintégrations B+→D+K(*)0. Ces modes de désintégration sont intéressants car il s'agit de processus d'annihilation qui fournit des informations importantes sur la dynamique de la désintégration des mésons beaux et les éléments de la matrice CKM, Vij. Les résultats obtenus sur ces modes de désintégration peuvent être utilisés dans des ajustements phénoménologiques. Cela permet de traduire les mesures sur les amplitudes chargées B+→D+K(*)0 en estimations sur les amplitudes B0→D0K(*)0 supprimées par Vub. L'analyse expérimentale est effectuée en utilisant plusieurs modes de désintégration du méson D chargé. Nous n'avons obtenu aucune évidence significative de signal et les limites supérieures sur les rapports d'embranchement suivants ont été établies. Dans la deuxième partie de la thèse nous présentons des études sur la violation de CP dans le système des mésons B et en particulier la mesure de l'angle γ du Triangle d'Unitarité. L'angle γ est la phase relative entre les éléments Vub et Vcb de la matrice CKM. Un paramètre crucial qui détermine la sensibilité à γ est le rapport r entre les amplitudes de transition b→u et b→c. Dans cette thèse nous présentons une analyse du canal de désintégration des mésons B: B+→D0K+. Ces désintégrations sont étudiées en utilisant la méthode ADS et le méson neutre D est reconstruit dans son état final Kππ0. En combinant cette analyse avec une analyse similaire qui utilise l'état final Kπ des D0 le rapport r et l'angle γ ont été déterminés.

Thesis (Ph. D.)--University of Chicago, Department of Physics, December 2001. / Includes bibliographical references. Also available on the Internet.

The concept of time in physics underwent significant changes in the decades following World War II. This dissertation considers several ways in which American physicists grappled with these changes, analyzing the extent to which philosophical methods and questions played a role in physicists' engagement with time. Two lines of questioning run through the dissertation. The first asks about the professional identities of postwar American physicists in relation to philosophy, as exemplified by their engagement with the concept of time. The second analyzes the heterogeneous nature of time in physics, and the range of presuppositions and assumptions that have constituted this "fundamental" physical concept. The first chapter looks to the development of atomic clocks and atomic time standards from 1948-1958, and the ways in which new timekeeping technologies placed concepts such as “clock”, “second,” and “measure of time” in a state of flux. The second chapter looks to the experimental discovery of CP violation by particle physicists in the early 1960s, raising questions about nature of time understood as the variable “t” in the equations of quantum mechanics. The third chapter considers attempts to unify quantum mechanics and general relativity in the late 1960s, which prompted physicists to question the “existence” of time in relation to the universe as a whole. In each episode considered, physicists engaged with the concept of time in a variety of ways, revealing a multiplicity of relationships between physics, philosophy, and time. Further, in each case physicists brought a unique set of assumptions to their concepts of time, revealing the variety ways in which fundamental conceptsfunctioned and changed in late twentieth century physics. The result is a heterogeneous picture of the practice of physics, as well as one of physics’ most basic concepts. / History of Science

The observation of a permanent electric dipole moment (EDM) in a non-degenerate system would indicate the violation of discrete symmetries of Time reversal (T) or combined application of Charge (C) and Parity (P) symmetry violation through the CPT theorem. The diamagnetic 225Ra atom with nuclear spin I=1/2 is a favorable candidate for an EDM search. Experimental sensitivity to its EDM is enhanced due to its high atomic mass and the increased Schiff moment of its octupole deformed nucleus. An experimental setup is developed where laser cooled neutral radium atoms are collected in a magneto-optical trap (MOT). The collected atoms are transported 1 meter with a far off-resonant optical dipole trap (ODT) and then the atoms are transferred to a second standing-wave ODT in an experimental chamber. The atoms are then optically polarized and allowed to Larmor precess in parallel and antiparallel electric and magnetic fields. The difference between the Larmor precession frequency for parallel and antiparallel fields is experimentally determined to measure the EDM. This thesis is about the first measurement of the EDM of the 225Ra atom where an upper limit of |d(225Ra)|<5.0*10-22 e cm (95\% confidence) is reached.

No description available.

The LHCb experiment is dedicated to making precision measurements involving beauty and charm hadrons at the CERN Large Hadron Collider. The LHCb RICH detectors provide charged particle identification required to distinguish final states in many decays important to the LHCb physics programme. Time alignment of the RICH photon detectors is necessary in order to ensure a high photon collection efficiency. Using both a pulsed laser and proton-proton collision data the photon detectors are aligned to within 1 ns. The LHCb detector is uniquely positioned to measure production cross-sections at energies and rapidities inaccessible to other experiments. With 1.81 nb−1 of proton-proton collisions collected by the LHCb experiment in 2010 at center-of-mass energy √s = 7 TeV the production crosssection of D±s and D± mesons decaying to the φ{K+K−}π ± final state have been determined in bins of transverse momentum and rapidity. These measurements use a data-driven recursive optimisation technique to improve signal significance. The cross-section ratio is measured to be σ(D± ) σ(D± s ) = 2.32±0.27(stat)±0.26(syst), consistent with the ratio of charm-quark hadronisation fractions to D± and D±s mesons. Time-dependent interference between mixing of B0s -B0s mesons and decay to the final state J/ψφ gives rise to a CP violating phase φs. This phase is constrained to be small within the Standard Model, a significant deviation from which would be a signal of new physics. φs has been measured with 0.37 fb−1 of protonproton collision data recorded during 2011 by the LHCb experiment. Isolation of the signal distribution is achieved using the S-plot technique, and the analysis accounts for inclusive B0s →J/ψK+K− s-wave contributions. The measured value of φs = 0.16±0.18(stat)±0.06(syst) rad is the most precise measurement to date, and is consistent with Standard Model predictions.

CP violation is an important condition to explain the preponderance of baryons in our universe, yet the available CP violation in the Standard Model (SM) via the so-called Cabibbo-Kobayashi-Maskawa mechanism seems to not provide enough CP violation. Thus searching for new sources of CP violation is one of the central tasks of modern physics. In this thesis, we focus on a new possible source of CP violation which generates triple-product correlations in momenta which can appear in neutron and nuclear radiative β decay. We show that at low energies such a CP violating correlation may arise from the exotic coupling of nucleon, photon and neutrino that was proposed by Harvey, Hill, and Hill (HHH). One specialty of such an exotic HHH coupling is that it does not generate the well-known CP-violating terms such as ``D-term'', ``R-term'', and neutron electric dipole moment, in which particle's spins play critical role. We show that such a new HHH-induced CP violating effect is proportional to the imaginary part of c5gv, where gv is the vector coupling constant in neutron and nuclear β decay, and c5 is the phenomenological coupling constant that appears in chiral perturbation theory at O(M-2) with M referring to the nucleon or nuclear mass. We consider a possible non-Abelian hidden sector model, which is beyond the SM and may yield a nontrivial Im(c5). The available bounds on both Im(c5) and Im(gv) are considered, and a better limit on Im(c5) can come from a direct measurement in radiative beta decay. We calculate the competitive effect that arises from the general parameterization of the weak interaction that was proposed by Lee and Yang in 1956. We also show that in the proposed measurements, the CP-violating effect can be mimicked by the SM via final-state interactions (FSI). For a better determination of the bound of Im(c5), we consider the FSI-induced mimicking effect in full detail in O(α) as well as in leading recoil order. To face ongoing precision measurements of neutron radiative β decay of up to 1% relative error, we sharpen our calculations of the CP conserving pieces of neutron radiative β decay by considering the largest contributions in O(α2): the final-state Coulomb corrections as well as the contributions from two-photon radiation.

In this thesis, using a general model independent form of the effective Hamiltonian, the CP-violating asymmetries in the b -&gt / d l l transition, when one of the leptons is polarized, is investigated. The sensitivity of the CP-violating asymmetries on the new Wilson coefficients are analyzed. Next, in the frame work of the same formalism, the polarized lepton pair forward&amp / #8211 / backward asymmetries in B-&gt / K l l decay are studied. We present the general expression for the nine double&amp / #8211 / polarization forward&amp / #8211 / backward asymmetries. It is obtained that, the zero point position of the forward&amp / #8211 / backward asymmetries of the doubly&amp / #8211 / polarized lepton pair does not depend on long distance effects but depends on short distance dynamics. Furthermore, it is shown that the zero position of AFB is very sensitive to the sign of the new Wilson coefficients. When sign of the Wilson coefficients is positive (negative) the zero position of the forward&amp / #8211 / backward asymmetries shifts to the left(right) compared to the SM. Moreover, the dependencies of the nine double&amp / #8211 / polarization forward&amp / #8211 / backward asymmetries on new Wilson coefficients, and the correlation of the averaged nine double&amp / #8211 / polarization forward&amp / #8211 / backward asymmetries with branching ratio, have been studied. It is observed that, the study of the nine double&amp / #8211 / polarization forward&amp / #8211 / backward asymmetries can serve as a good test in establishing new physics beyond the Standard Model. Finally, we observed that there are exist such regions of new Wilson coefficients for which the nine double&amp / #8211 / polarization forward&amp / #8211 / backward asymmetries considerably depart from the SM result, while the branching ratio coincides with that of the SM prediction. In other words, new physics effects can be established by analyzing polarized forwardbackward asymmetry in this region of the new Wilson coefficients.