1,720,993 research outputs found
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
Overview and theoretical prospects for CKM matrix and CP violation from the UTfit Collaboration
No full textInternational audiencePrecision studies of the Cabibbo-Kobayashi-Maskawa matrix offer a very important testbed of the Standard Model (SM).In light of new inputs and measurements, in this proceeding we review the status of the Unitarity Triangle as a fundamental tool to uncover New Physics. We report the results of the latest SM global fits performed by the UTfit Collaboration including all the up-to-date experimental and theoretical inputs as for the Summer 2023 release.We also update the stringent constraints on New Physics from the generalized effective Hamiltonian. We conclude highlighting the role of the Unitarity Triangle for future indirect searches on New Physics
Determination of |Vub| using the lepton energy spectrum in events tagged with a fully reconstructed B meson
No full textPhDWe present measurements of partial branching fractions for the inclusive semileptonic decay
of B ! Xu` (` = e or ) leading to the determination of the CKM matrix element jVubj.
This analysis is based on a sample of 460 million BB events recorded at the (4S) resonance
at the BABAR detector.
We select B ! Xu` events using the energy spectrum of the lepton (E`) in an event
where one of the B-mesons is fully reconstructed. We measure partial branching fractions
in restricted regions of the E` spectrum, which are translated into values of jVubj using four
theoretical approaches. We calculate the arithmetic mean, using the results from the four
theoretical approaches at E` > 1:5 GeV resulting in: jVubj = (4:68+0:31
0:32) 103. The analysis
presented in this thesis is the rst time a measurement of jVubj has been performed using the
E` spectrum in events tagged with a fully reconstructed B meson
The 2004 UTfit Collaboration Report on the Status of the Unitarity Triangle in the Standard Model
No full text32 pages, 17 figures. High resolution figures and updates can be found at http://www.utfit.org v2: misprints correctedUsing the latest 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 |V_ub/V_cb|, Delta M_d, the lower limit on Delta M_s, epsilon_k, and the measurement of the phase of the B_d - anti B_d mixing amplitude through the time-dependent CP asymmetry in B^0 to J/psi K^0 decays. In addition, we consider the direct determination of alpha, gamma, 2 beta + gamma and cos(2 beta) from the measurements of new CP-violating quantities, recently performed at the B factories. We also discuss the opportunities offered by improving the precision of the various physical quantities entering in the determination of the Unitarity Triangle parameters. The results and the plots presented in this paper can also be found at http://www.utfit.org, where they are continuously updated with the newest experimental and theoretical results
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
CP violation in Bs mixing in the SUSY SU(5) GUT with right-handed neutrinos
No full textAbstractIt is recently announced by the UTfit Collaboration that the CP phase of the Bs mixing amplitude, ϕBs, deviates more than 3σ from the Standard Model prediction. In this Letter we discuss how large correction to ϕBs is possible in the supersymmetric SU(5) ground unified model (SUSY SU(5) GUT) with right-handed neutrinos. Here, we assume the supergravity-like boundary condition for the SUSY-breaking terms. We found that the 95% probability region derived by the UTfit Collaboration is marginal in this model
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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