8,332 research outputs found

    Heavy Flavours and CP Violation

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    Recent results on Heavy Flavours and CP violation are presented. After a short introduction a taste of K and D results is given. In a third part results on Vtd and Vts are summaryzed including BBbar mixing results and Bd radiative decays. A summary of Vcb and Vub measurements is presented in the fourth part. In the next section CP violation measurements in the Bd sector are shown. Finally in the last part the overall status of the determination of the CKM matrix is presented both in the context of the Standard Model and in the context of New Physics.Comment: Plenary talk at HEP200

    Overall determination of the CKM matrix

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    We discuss the problem of theoretical uncertainties in the combination of observables related to the CKM matrix elements and propose a statistically sensible method for combining them. The overall fit is performed on present data, and constraints on the matrix elements are presented as well as on fB*sqrt(Bb). We then explore the implications of recent measurements and developments: jpsi-KS CP asymmetry, epsilon_prime/epsilon and B -> K pi branching fractions. Finally, we extract from the overall fit the Standard Model expectations for the rare kaon decays K -> pi nu anti-nu.Comment: Talk given at Heavy Flavours 8, Southampton, UK, 199

    Feasibility study for a model independent measurement of 2ÎČ+Îł\beta + \gamma in B0B^0 decays using D−K0π+D^- K^0 \pi^+ final states

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    In this paper we present a feasibility study for measuring the combination of the Unitarity Triangle angle 2ÎČ+Îł\beta +\gamma with a time dependent Dalitz analysis in B0B^0 decays using D−K0π+D^- K^0 \pi^+ final states following the method proposed in [1]. For this study we build a model for this decay using the latest experimental information and we investigate the possibility of fitting together with 2ÎČ+Îł\beta +\gamma all the relevant strong amplitudes and phases of the decay model. [1] R. Aleksan, T.C. Petersen and A. Soffer, Phys. Rev. D67 (2003) 096002 [hep-ph/0209194].Comment: 14 page

    Search for new physics at LHCb: rare decays of B hadrons and CP violation in the charm sector

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    PoS(EPS-HEP 2009) 186 - On behalf of the LHCb collaborationInternational audienceLHCb is an heavy flavour precision experiment with LHC at CERN. It will search for New Physics in CP violation and rare decays in the heavy quarks sector. The experiment is ready to take data for the soon expected start-up of the LHC. An overview of its physics program in both the rare decays of B hadrons and CP violation in the charm sectors is given, illustrated by few key examples: measurements of the \bstomumu\ and \btokstmumu\ decay modes, study of the photon helicity using the \bstophig\ and \btokstee\ decay modes, as well as search for CP violation using D^0 meson

    Renormalization of heavy-light currents in moving NRQCD

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    Heavy-light decays such as B→πℓΜB \to \pi \ell \nu, B→K∗γB \to K^{*} \gamma and B→K(∗)ℓℓB \to K^{(*)} \ell \ell can be used to constrain the parameters of the Standard Model and in indirect searches for new physics. While the precision of experimental results has improved over the last years this has still to be matched by equally precise theoretical predictions. The calculation of heavy-light form factors is currently carried out in lattice QCD. Due to its small Compton wavelength we discretize the heavy quark in an effective non-relativistic theory. By formulating the theory in a moving frame of reference discretization errors in the final state are reduced at large recoil. Over the last years the formalism has been improved and tested extensively. Systematic uncertainties are reduced by renormalizing the m(oving)NRQCD action and heavy-light decay operators. The theory differs from QCD only for large loop momenta at the order of the lattice cutoff and the calculation can be carried out in perturbation theory as an expansion in the strong coupling constant. In this paper we calculate the one loop corrections to the heavy-light vector and tensor operator. Due to the complexity of the action the generation of lattice Feynman rules is automated and loop integrals are solved by the adaptive Monte Carlo integrator VEGAS. We discuss the infrared and ultraviolet divergences in the loop integrals both in the continuum and on the lattice. The light quarks are discretized in the ASQTad and highly improved staggered quark (HISQ) action; the formalism is easily extended to other quark actions.Comment: 24 pages, 11 figures. Published in Phys. Rev. D. Corrected a typo in eqn. (51

    Performances of Anode-resistive Micromegas for HL-LHC

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    Micromegas technology is a promising candidate to replace Atlas forward muon chambers -tracking and trigger- for future HL-LHC upgrade of the experiment. The increase on background and pile-up event probability requires detector performances which are currently under studies in intensive RD activities. We studied performances of four different resistive Micromegas detectors with different read-out strip pitches. These chambers were tested using \sim120 GeV momentum pions, at H6 CERN-SPS beam line in autumn 2010. For a strip pitch 500 micrometers we measure a resolution of \sim90 micrometers and a efficiency of ~98%. The track angle effect on the efficiency was also studied. Our results show that resistive techniques induce no degradation on the efficiency or resolution, with respect to the standard Micromegas. In some configuration the resistive coating is able to reduce the discharge currents at least by a factor of 100.Micromegas technology is a promising candidate to replace Atlas forward muon chambers -tracking and trigger- for future HL-LHC upgrade of the experiment. The increase on background and pile-up event probability requires detector performances which are currently under studies in intensive RD activities. We studied performances of four different resistive Micromegas detectors with different read-out strip pitches. These chambers were tested using \sim120 GeV momentum pions, at H6 CERN-SPS beam line in autumn 2010. For a strip pitch 500 micrometers we measure a resolution of \sim90 micrometers and a efficiency of \sim98%. The track angle effect on the efficiency was also studied. Our results show that resistive techniques induce no degradation on the efficiency or resolution, with respect to the standard Micromegas. In some configuration the resistive coating is able to reduce the discharge currents at least by a factor of 100.Comment: "Presented at the 2011 Hadron Collider Physics symposium (HCP-2011), Paris, France, November 14-18 2011, 3 pages, 6 figures.

    Aging studies of Micromegas prototypes for the HL-LHC

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    The micromegas technology is a promising candidate to replace the forward muon chambers for the luminosity upgrade of ATLAS. The LHC accelerator luminosity will be five times the nominal one, increasing background and pile-up event probability. This requires detector performances which are currently under study in intensive R&D activities. Aging is one of the key issues for a high-luminosity LHC application. For this reason, we study the properties of resistive micromegas detectors under intense X-ray radiation and under thermal neutrons in different CEA-Saclay facilities. This study is complementary to those already performed using fast neutrons.Comment: Proceedings of the MPGD2011 Conferenc
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