6,363 research outputs found

    Rare b hadron decays at the LHC

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    With the completion of Run~I of the CERN Large Hadron Collider, particle physics has entered a new era. The production of unprecedented numbers of heavy-flavoured hadrons in high energy proton-proton collisions allows detailed studies of flavour-changing processes. The increasingly precise measurements allow to probe the Standard Model with a new level of accuracy. Rare bb hadron decays provide some of the most promising approaches for such tests, since there are several observables which can be cleanly interpreted from a theoretical viewpoint. In this article, the status and prospects in this field are reviewed, with a focus on precision measurements and null tests.Comment: Invited review for Annual Reviews of Nuclear and Particle Physics. v2 as publishe

    Complexity in parametric Bose-Hubbard Hamiltonians and structural analysis of eigenstates

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    We consider a family of chaotic Bose-Hubbard Hamiltonians (BHH) parameterized by the coupling strength kk between neighboring sites. As kk increases the eigenstates undergo changes, reflected in the structure of the Local Density of States. We analyze these changes, both numerically and analytically, using perturbative and semiclassical methods. Although our focus is on the quantum trimer, the presented methodology is applicable for the analysis of longer lattices as well.Comment: 4 pages, 4 figure

    A Comparative Study of the Decays B→(K,K∗)ℓ+ℓ−B \to (K,K^*) \ell^+ \ell^- in Standard Model and Supersymmetric Theories

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    Using improved theoretical calculations of the decay form factors in the Light Cone-QCD sum rule approach, we investigate the decay rates, dilepton invariant mass spectra and the forward-backward (FB) asymmetry in the decays B→(K,K∗)ℓ+ℓ−B \to (K,K^*) \ell^+ \ell^- (ℓ±=e±,Ό±,τ±\ell^\pm =e^\pm,\mu^\pm,\tau^\pm) in the standard model (SM) and a number of popular variants of the supersymmetric (SUSY) models. Theoretical precision on the differential decay rates and FB-asymmetry is estimated in these theories taking into account various parametric uncertainties. We show that existing data on B→XsÎłB \to X_s \gamma and the experimental upper limit on the branching ratio B(B→K∗Ό+Ό−){\cal B}(B \to K^* \mu^+ \mu^-) provide interesting bounds on the coefficients of the underlying effective theory. We argue that the FB-asymmetry in B→K∗ℓ+ℓ−B \to K^* \ell^+ \ell^- constitutes a precision test of the SM and its measurement in forthcoming experiments may reveal new physics. In particular, the presently allowed large-tan⁥ÎČ\tan \beta solutions in SUGRA models, as well as more general flavor-violating SUSY models, yield FB-asymmetries which are characteristically different from the corresponding ones in the SM.Comment: 36 pages, 12 figures (require epsfig.sty), 8 Tables, LaTeX2e; subsection 6.4 corrected, minor changes in numerical results, Figures 3 and 9 to 12 modified; submitted to Physical Review

    Visualizing the Intersection of the Personal and the Social Context - The Use of Multi-layered Chronological Charts in Biographical Studies

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    This paper outlines the theoretical reasoning and technical implementation of a particular approach to creating multi-layered chronological charts in qualitative biographical studies. The discussed method elucidates the interpretation of traditional life chronologies where the individual\u27s objective life facts are reconstructed free from analysis. The novelty of multi-layered chronological charts lies in their ability to enrich the visualization of a temporal connection between personal and social contextual factors based on categories determined by the researcher. In doing so, such charts make existing interview data more accessible and processable. In-depth, thematic data analysis can be supported through the visualization of prominent life aspects or the presentation of integrative perspectives of individuals\u27 lives. Case examples are presented to demonstrate how methodological and theoretical objectives are fulfilled through the customized use of genealogy software. Based on the underlying research problem, multi-layered biographical charts can be customized for different research purposes and connected to an array of complex linkage systems

    Labor Unionism and Convict Labor

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