1,721,035 research outputs found
Lattice QCD confronts the unitarity triangle fit.
No full textBefore the starting of the B factories, the Unitarity Triangle (UT) analysis relied on the results of lattice QCD simulations to relate the experimental determinations of semileptonic B decays, K0 - over(K, -)0 and Bd, s 0 - over(B, -)d, s 0 mixing to the CKM parameters. In the last years, much more information has been obtained from the direct determination of the UT angles from non-leptonic B decays. In this talk, we compare the results of the "classical" UT analysis (UTlattice) with the analysis based on the angles determinations (UTangles). We show that the recent measurement of Δ ms, combined with Δ md and εK, allows from this comparison a quite accurate extraction of the values of the lattice parameters, over(B, ̂)K, fB s over(B, ̂)B s 1 / 2, ξ and fB. These values, obtained "experimentally" by assuming the validity of the Standard Model, can be compared with the theoretical predictions from lattice QCD. We also discuss the different determinations of Vu b and show that current data do not favor the value measured in inclusive decays. Finally, we present updated predictions for the leptonic branching fraction B R (B → τ ντ), and compare them with the recent experimental determination. We take the opportunity of this write up to update the results of ref. [M. Bona et al. [UTfit Collaboration], arXiv:hep-ph/0606167] with the most recent results presented at the ICHEP'06 conference. © 2006 Elsevier B.V. All rights reserved
Updates in the Unitarity Triangle fits with UTfit
No full textIn these proceedings, the results of the latest Standard Model analysis performed by the UTfit collaboration including the most updated inputs from experiments, lattice QCD and phenomenological calculations as of Summer 2021 are presented. In addition, the results of a New Physics analysis in which the most generic loops to all sectors have been added are also reported, together with the New Physics contributions to transitions
CKM fits and model-independent constraints on physics BSM
No full textOn behalf of the UTFit Collaboratio
New UTfit Analysis of the Unitarity Triangle in the Cabibbo-Kobayashi-Maskawa scheme
Full text linkInternational audienceFlavour mixing and CP violation as measured in weak decays and mixing of neutral mesons are a fundamental tool to test the Standard Model (SM) and to search for new physics. New analyses performed at the LHC experiment open an unprecedented insight into the Cabibbo-Kobayashi-Maskawa (CKM) metrology and new evidence for rare decays. Important progress has also been achieved in theoretical calculations of several hadronic quantities with a remarkable reduction of the uncertainties. This improvement is essential since previous studies of the Unitarity Triangle did show that possible contributions from new physics, if any, must be tiny and could easily be hidden by theoretical and experimental errors. Thanks to the experimental and theoretical advances, the CKM picture provides very precise SM predictions through global analyses. We present here the results of the latest global SM analysis performed by the UTfit collaboration including all the most updated inputs from experiments, lattice QCD and phenomenological calculations
New UTfit Analysis of the Unitarity Triangle in the Cabibbo-Kobayashi-Maskawa scheme
Full text linkFlavour mixing and CP violation as measured in weak decays and mixing of neutral mesons are a fundamental tool to test the Standard Model and to search for new physics. New analyses performed at the LHC experiment open an unprecedented insight into the Cabibbo–Kobayashi–Maskawa metrology and new evidence for rare decays. Important progress has also been achieved in theoretical calculations of several hadronic quantities with a remarkable reduction of the uncertainties. This improvement is essential since previous studies of the Unitarity Triangle did show that possible contributions from new physics, if any, must be tiny and could easily be hidden by theoretical and experimental errors. Thanks to the experimental and theoretical advances, the Cabibbo–Kobayashi–Maskawa picture provides very precise Standard Model predictions through global analyses. We present here the results of the latest global Standard Model analysis performed by the UTfit collaboration including all the most updated inputs from experiments, lattice Quantum Chromo-Dynamics and phenomenological calculations
Unitarity Triangle analysis beyond the Standard Model from UTfit
No full textThe Unitarity Triangle (UT) analysis can be used to constrain the parameter space in possible new physics (NP) scenarios. We present here an update of the UT analysis beyond the Standard Model (SM) by the UTfit collaboration. Assuming NP, all of the available experimental and theoretical information on ∆F = 2 processes is combined using a model-independent parametrisation. We determine the allowed NP contributions in the kaon, D, Bd, and Bs sectors and, in various NP scenarios, we translate them into bounds for the NP scale as a function of NP couplings
Current status of the CKM matrix
No full textUsing recent determinations of several theoretical and experimental parameters, we update the Unitarity Triangle analysis in the Standard Model. The basic experimental constraints come from the measurements of epsilon K, vertical bar V-ub/V-cb vertical bar, and Delta m(d), the limit on Delta m(s), and the measurement of the CP asymmetry in the B sector through sin 2 beta. We include in our analysis the direct determination of sin 2 alpha, gamma, and sin(2 beta + gamma) from the measurements of new CP-violating quantities. The results and the plots presented here can be also found at the URL http://www.utfit.org
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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