9,889 research outputs found

    CP violation and limits on New Physics including recent BsB_s measurements

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    We analyse present constraints on the SM parameter space and derive, in a model independent way, various bounds on New Physics contributions to Bd0B_d^0--Bˉd0\bar B_d^0 and Bs0B_s^0--Bˉs0\bar B_s^0 mixings. Our analyses include information on a large set of asymmetries, leading to the measurement of the CKM phases Îł\gamma and ÎČˉ\bar\beta, as well as recent data from D0 and CDF related to the Bs0B_s^0--Bˉs0\bar B_s^0 system such as the measurement of ΔMBs\Delta M_{B_s}, ASLA_{SL} and ΔΓsCP\Delta\Gamma_{s}^{CP}. We examine in detail several observables such as the asymmetries AsldA_{sl}^d, ASLA_{SL}, the width differences ΔΓd\Delta\Gamma_{d} and ΔΓsCP\Delta\Gamma_{s}^{CP} and discuss the r\^ole they play in establishing the limits on New Physics. The present data clearly favour the SM, with the New Physics favoured region placed around the SM solution. A New Physics solution significantly different from the SM is still allowed, albeit quite disfavoured (2.6% probability). We analyse the presently available indirect knowledge on the phase χˉ\bar\chi entering in Bs0B_s^0--Bˉs0\bar B_s^0 mixing and study the impact of a future measurement of χˉ\bar\chi to be achieved at LHC, through the measurement of the time-dependent CP asymmetry in Bs→J/ΚΊB_s\to J/\Psi \Phi decays.Comment: 29 pages, 31 figures; updated analyses and reference

    Nonleptonic charmless two-body B→ATB \to AT decays

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    In this work we have studied hadronic charmless two-body B decays involving p-wave mesons in final state. We have calculated branching ratios of B→ATB\to AT decays (where AA and TT denotes a 3P1^3P_1 axial-vector and a tensor meson, respectively), using B→TB \to T form factors obtained in the covariant light-front (CLF) approach, and the full effective Hamiltonian. We have obtained that B(B0→a1+a2−)=42.47×10−6\mathcal{B}(B^{0} \to a_{1}^{+}a_{2}^{-}) =42.47 \times10^{-6}, B(B+→a1+a20)=22.71×10−6\mathcal{B}(B^{+} \to a_{1}^{+}a_{2}^{0}) = 22.71 \times10^{-6}, B(B→f1K2∗)=(2.8−4)×10−6\mathcal{B}(B \to f_{1}K_{2}^{*}) = (2.8-4) \times 10^{-6} (with f1=,f1(1285),f1(1420)f_{1}=, f_{1}(1285),f_{1}(1420)) for ξ3P1=53.2∘\theta_{^{3}P_{1}} = 53.2^{\circ}, B(B→f1(1420)K2∗)=(5.91−6.42)×10−6\mathcal{B}(B \to f_{1}(1420)K_{2}^{*}) = (5.91-6.42) \times 10^{-6} with ξ3P1=27.9∘\theta_{^{3}P_{1}} = 27.9^{\circ}, B(B→K1a2)=(1.7−5.7)[1−9.3]×10−6\mathcal{B}(B \to K_{1}a_{2})= (1.7 - 5.7) [1-9.3] \times10^{-6} for ξK1=−37∘[−58∘]\theta_{K_{1}} = -37^{\circ} [-58^{\circ}] where K1=K1(1270),K1(1400)K_1 = K_1(1270), K_1(1400). It seems that these decays can be measured in experiments at BB factories. Additionally, we have found that B(B→K1(1270)a2)/B(B→K1(1400)a2)\mathcal{B}(B \to K_{1}(1270)a_{2})/\mathcal{B}(B \to K_{1}(1400)a_{2}) and B(B→f1(1420)K2∗)/B(B→f1(1285)K2∗)\mathcal{B}(B \to f_1(1420)K_{2}^{*})/\mathcal{B}(B \to f_1(1285)K_{2}^{*}) ratios could be useful to determine numerical values of mixing angles ξK1\theta_{K_{1}} and ξ3P1\theta_{^{3}P_{1}}, respectively.Comment: 12 page

    An Improved Standard Model Prediction Of BR(B -> tau nu) And Its Implications For New Physics

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    The recently measured B -> tau nu branching ratio allows to test the Standard Model by probing virtual effects of new heavy particles, such as a charged Higgs boson. The accuracy of the test is currently limited by the experimental error on BR(B -> tau nu) and by the uncertainty on the parameters fB and |Vub|. The redundancy of the Unitarity Triangle fit allows to reduce the error on these parameters and thus to perform a more precise test of the Standard Model. Using the current experimental inputs, we obtain BR(B -> tau nu)_SM = (0.84 +- 0.11)x10^{-4}, to be compared with BR(B -> tau nu)_exp = (1.73 +- 0.34)x10^{-4}. The Standard Model prediction can be modified by New Physics effects in the decay amplitude as well as in the Unitarity Triangle fit. We discuss how to disentangle the two possible contributions in the case of minimal flavour violation at large tan beta and generic loop-mediated New Physics. We also consider two specific models with minimal flavour violation: the Type-II Two Higgs Doublet Model and the Minimal Supersymmetric Standard Model.Comment: 7 pages, 13 figures, 1 table. v2: added references and discussion of B -> D tau nu in the 2HDM. v3: added Bs->mumu in the 2HDM. Final version to appear in PL

    Perspectives on IT Outsourcing Success: Covariance Structure Modelling of a Survey of Outsourcing in Australia

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    Australia has been at the forefront of the adoption of outsourcing as a means for delivering IT services, but the success of IT outsourcing in Australia has been mixed. With two hundred and forty one responses from the top 1000 IT users in the country, the survey reported in this paper is one of the largest and most representative IT outsourcing studies in the world. Covariance structure modelling and confirmatory factor analysis has shed new light on the concept of outsourcing success, highlighting its complex, multidimensional nature. It has also confirmed many insights gained to date from qualitative research. Analysis also emphasises the importance to the outsourcing relationship of the management processes adopted by the client organization. L'Australie a Ă©tĂ© un pionnier dans l'adoption de l'impartition pour les services informatiques. Toutefois, les rĂ©sultats ont Ă©tĂ© mitigĂ©s. Avec plus de deux cent rĂ©pondants, provenant des 1000 plus grandes entreprises australiennes, cette Ă©tude et une des plus larges et reprĂ©sentatives faites jusqu'Ă 0501ntenant. Une analyse des structure de co-variance, de mĂȘme qu'une anlayse factorielle confirmatoire jettent un regard neuf sur la notion de succĂšs de l'impartition. L'Ă©tude met en lumiĂšre le caractĂšre complexe et multi-dimensionel de ce succĂšs.Outsourcing, Australia, survey research, success, information systems, Impartition, Australie, enquĂȘte, succĂšs, services informatiques

    Radiative and Semileptonic B Decays Involving Higher K-Resonances in the Final States

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    We study the radiative and semileptonic B decays involving a spin-JJ resonant KJ(∗)K_J^{(*)} with parity (−1)J(-1)^J for KJ∗K_J^* and (−1)J+1(-1)^{J+1} for KJK_J in the final state. Using the large energy effective theory (LEET) techniques, we formulate B→KJ(∗)B \to K_J^{(*)} transition form factors in the large recoil region in terms of two independent LEET functions ζ⊄KJ(∗)\zeta_\perp^{K_J^{(*)}} and ζ∄KJ(∗)\zeta_\parallel^{K_J^{(*)}}, the values of which at zero momentum transfer are estimated in the BSW model. According to the QCD counting rules, ζ⊄,∄KJ(∗)\zeta_{\perp,\parallel}^{K_J^{(*)}} exhibit a dipole dependence in q2q^2. We predict the decay rates for B→KJ(∗)ÎłB \to K_J^{(*)} \gamma, B→KJ(∗)ℓ+ℓ−B \to K_J^{(*)} \ell^+ \ell^- and B→KJ(∗)ΜΜˉB \to K_J^{(*)}\nu \bar{\nu}. The branching fractions for these decays with higher KK-resonances in the final state are suppressed due to the smaller phase spaces and the smaller values of ζ⊄,∄KJ(∗)\zeta^{K_J^{(*)}}_{\perp,\parallel}. Furthermore, if the spin of KJ(∗)K_J^{(*)} becomes larger, the branching fractions will be further suppressed due to the smaller Clebsch-Gordan coefficients defined by the polarization tensors of the KJ(∗)K_J^{(*)}. We also calculate the forward backward asymmetry of the B→KJ(∗)ℓ+ℓ−B \to K_J^{(*)} \ell^+ \ell^- decay, for which the zero is highly insensitive to the KK-resonances in the LEET parametrization.Comment: 27 pages, 4 figures, 7 tables;contents and figures corrected, title and references revise

    Initial Conditions for Large Cosmological Simulations

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    This technical paper describes a software package that was designed to produce initial conditions for large cosmological simulations in the context of the Horizon collaboration. These tools generalize E. Bertschinger's Grafic1 software to distributed parallel architectures and offer a flexible alternative to the Grafic2 software for ``zoom'' initial conditions, at the price of large cumulated cpu and memory usage. The codes have been validated up to resolutions of 4096^3 and were used to generate the initial conditions of large hydrodynamical and dark matter simulations. They also provide means to generate constrained realisations for the purpose of generating initial conditions compatible with, e.g. the local group, or the SDSS catalog.Comment: 12 pages, 11 figures, submitted to ApJ

    What can we learn from phi_1 and B_d^0 -> pi^+ pi^- ?

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    We discuss what we can understand from ϕ1\phi_1 and Bd0→π+π−B^0_d\to \pi^+ \pi^- decay mode. Using a convention without weak phases ϕ2\phi_2 and ϕ3\phi_3, we can solve the parameters from the time-depended CP asymmetry. If we can put a condition the contribution from penguin except for the CKM factor including in the diagram is small, then we can lead the allowed region of RtR_t or ϕ2\phi_2 by using the convention.Comment: 7 pages, 4 figures, references and comments adde
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