1,479 research outputs found

    Hunting the CKM weak phase with time-integrated Dalitz analyses of Bs -> K pi pi decays

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    We present a new technique to extract information on the Unitarity Triangle from the study of Bs -> K pi pi Dalitz plot. Using isospin symmetry and the possibility to access the decay amplitudes from Dalitz analyses, we propose a new strategy to extract the weak phase gamma from Bs to K pi pi.Comment: 2 pages. v2: Discussion of interference on Dalitz plot clarified. Bs -> K K pi channels removed. v3: Improved discussion of experimental aspects. Final version to appear in Phys. Lett.

    Opportunities From Precision Flavour Physics

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    The possible role of precision flavour physics, and particularly of B physics, in the next decade is briefly discussed. Few 2--3σ\sigma deviations from the Standard Model found in present BB data are reviewed as potential forerunners of new physics signals to be looked for in next-generation experiments. The perspectives for theoretical calculations, in particular those based on lattice QCD, to match the expected progress in experimental precision are also discussed.Comment: 10 pages, 7 figures, proceedings of the 12th International Conference on B-Physics at Hadron Machines - BEAUTY 2009, September 07-12, 2009, Heidelberg, German

    NLO corrections to Delta F=2 effective Hamiltonians and SUSY contribution to FCNC

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    The most general QCD-NLO Anomalous-Dimension Matrix of all four-fermion dimension six Delta F=2 operators is presented. Two applications of this Anomalous-Dimension Matrix to the study of SUSY contribution to K- Kbar mixing are also discussed.Comment: 4 pages. Talk given at International Euroconference on Quantum Chromodynamics (QCD98), Montpellier, France, 2-8 july 1998. Submitted to Nucl. Phys. B (Proc. Suppl.

    Theoretical status of epsilon'/epsilon

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    We review the theory of epsilon'/epsilon and present an updated phenomenological analysis using hadronic matrix elements from lattice QCD. The present status of the computation of epsilon'/epsilon, considering various approaches to the matrix-element evaluation, is critically discussed.Comment: 22 pages, 2 eps figures, based on the talks given by M.C. at "Les Rencontres de Physique de la Vallee d'Aoste", La Thuile (Italy), 27 February-4 March 2000 and by G.M. at the "XXXVth Rencontres de Moriond", Les Arcs 1800 (France), 11-18 March 200

    Charming penguin and direct CP-violation in charmless B decays

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    In the study of two-body charmless B decays as a mean of looking for direct CP-violation and measuring the CKM mixing parameters in the Standard Model, the short-distance penguin contribution with its absorptive part generated by charm quark loop seems capable of producing sufficient BKπB \to K\pi decays rates, as obtained in factorization and QCD-improved factorization models. However there are also long-distance charming penguin contributions which could give rise to a strong phase due to the rescattering DDsKπD^{*}D^{*}_{s} \to K\pi etc. In this talk, I would like to discuss recent works on the charming penguin contribution as a different approach to the calculation of these contributions in two-body charmless B decays. We find that the charming penguin contribution is significant for BKπB\to K\pi decays and, together with the tree and penguin terms, produces large branching ratios in agreement with data, though the analysis is affected by large theoretical uncertainties. The absorptive part due to the charmed meson intermediate states is found to produce large CP asymmetries for BKπ,ππB \to K\pi, \pi\pi decays.Comment: Talk given at the QCD Euroconference 2002, Montpellier 2-9 July 2002, LaTex, 7 pages, Misprint in the Tables correcte

    CP violation in supersymmetric theories

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    We review the present status of CP violating problem in supersymmetric extensions of the standard model. We analyze the constraints imposed by the experimental limits of the electron, neutron, and mercury electric dipole moments on the supersymmetric CP phases and show that only the scenarios with flavour-off- diagonal CP violation remain attractive. These scenarios require hermitian Yukawa matrices which naturally arise in models with left-right symmetry or a SU(3) flavour symmetry. In this case, epsilon_K and epsilon'/epsilon can be saturated by a small non-universality of the soft scalar masses through the gluino and chargino contributions respectively. The model also predicts a strong correlation between A_{CP}(b-> s gamma) and the neutron electric dipole moment. In this framework, the standard model gives a the leading contribution to the CP asymmetry in B ->psi K_S decay, while the dominant chargino contribution to this asymmetry is < 0.2. Thus, no constraint is set on the non-universality of this model by the recent BaBar and Belle measureets.Comment: 34 pages, 10 figures. Invited review article for International Journal of Modern Physics

    Calcutation of kaon matrix elements in quenched domain-wall QCD with DBW2 gauge action

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    We give a progress report of our new a13a^{-1}\approx 3 GeV quenched calculation of kaon matrix elements with domain-wall fermion and DBW2 gauge action. Our smaller lattice spacing allows us to address the effect of charmed quark on the lattice. We show preliminary results of BKB_K renormalized non-perturbatively and KπK\to\pi matrix elements.Comment: Lattice2003(matrix), 3 pages, 6 figure
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