1,720,958 research outputs found
Highlights of top quark properties at ATLAS and CMS
No full textRecent measurements of top quark properties using data collected by the LHC experiments are presented. These results include latest measurements of the top quark mass, width, tt spin correlations and asymmetries. Moreover, searches for flavour-changing neutral currents involving top quarks are also discussed including tZq, and tHq couplings, in top quark pair and single top production
Highlights from the CMS Experiment
No full textDuring the LHC Run 2, the CMS experiment has so far recorded of proton–proton collision data at TeV. With such a large volume of data-set at an unprecedented energy, CMS has updated most of its new physics searches while the precision on various Standard Model measurements has substantially improved. This proceeding features most recent results on Higgs boson, Top quark, and new physics searches and the status of the CMS detector in 2017
Top Quark Decay Properties
No full textDue to the large production cross-section, many of the top quark properties can be measured very precisely at the LHC. A very few recent results, probed only through the top quark decay vertices are presented here. These results are based on proton-proton collision datasets recorded by the ATLAS and CMS experiments at sqrt(s)=7, 8 and 13 TeV. All the measurements and observed limits are consistent with the Standard Model (SM) predictions, while strong bounds on anomalous Wtb couplings are established
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Measurement of top anti-top cross section in proton - anti-proton collider at s**(1/2) = 1.96-TeV
No full textDiscovery of the top quark in 1995 at the Fermilab Tevatron collider concluded a long search following the 1977 discovery of bottom (b) quark [1] and represents another triumph of the Standard Model (SM) of elementary particles. Top quark is one of the fundamental fermions in the Standard Model of electroweak interactions and is the weak-isospin partner of the bottom quark. A precise measurement of top pair production cross-section would be a test of Quantum Chromodynamics (QCD) prediction. Presently, Tevatron is the world's highest energy collider where protons (p) and anti-protons ({anti p}) collide at a centre of mass energy (ps) of 1.96 TeV. At Tevatron top (t) and anti-top ({anti t}) quarks are predominantly pair produced through strong interactions--quark annihilation ({approx_equal} 85%) and gluon fusion ({approx_equal} 15%). Due to the large mass of top quark, t or {anti t} decays ({approx} 10{sup -25} sec) before hadronization and in SM framework, it decays to a W boson and a b quark with {approx} 100% branching ratio (BR). The subsequent decay of W boson determines the major signatures of t{anti t} decay. If both W bosons (coming from t and {anti t} decays) decay into leptons (viz., ev{sub e}, {mu}{nu}{sub {mu}} or {tau}{nu}{sub {tau}}) the corresponding t{bar t} decay is called dileptonic decay. Of all dileptonic decay modes of t{bar t}, the t{bar t} {yields} WWb{anti b} {yields} ev{sub e}{mu}{nu}{sub {mu}}b{anti b} (e{mu} channel) decay mode has the smallest background contamination from Z{sup 0} production or Drell-Yan process; simultaneously, it has the highest BR ({approx} 3.16%) [2] amongst all dileptonic decay modes of t{bar t}. During Run I (1992-1996) of Tevatron, three e{mu} candidate events were detected by D0 experiment, out of 80 candidate events (inclusive of all decay modes of t{bar t}). Due to the rarity of the t{bar t} events, the measured cross-section has large uncertainty in its value (viz., 5.69 {+-} 1.21(stat) {+-} 1.04(sys) pb {at} {radical}s = 1.8 TeV measured by D0 [3]). This analysis presents a cross section measurement in e{mu} channel utilizing {approx} 228 pb{sup -1} of data collected by D0 experiment during Tevatron Run II (between June 2002 and April 2004)
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SUSY Higgs Searches at D0, Tevatron
Full text linkDuring Run II of the Tevatron collider, D0 collaboration has made extensive searches for the neutral MSSM Higgs bosons ({phi}), produced in p{bar p} collisions at {radical}s = 1.96 TeV. Two such analyses, addressing inclusive {phi} production with {phi} {yields} {tau}{sup +}{tau}{sup -}, and associated {phi}b(b) production with {phi} {yields} b{bar b} are reported here. No excess of events above the background expectation has been observed in any of these analyses. The results are combined to set constraints on the MSSM parameter space
Search for Higgs Invisible Decays at the LHC
No full textThe recent discovery of the Standard Model (SM) Higgs boson at the LHC experiments (ATLAS and CMS) has finally culminated the long-standing puzzle of electroweak symmetry breaking (at least within the context of the SM), while broadening the scope of beyond the Standard Model (BSM) physics involving the Higgs boson itself. In particular, the characteristic decay of the SM Higgs boson into some particles which can escape detection by the modern High Energy Physics detectors (and thus becomes invisible) can be one of the interesting searches for the BSM physics. In various new physics models, plausible dark matter candidates e.g., Majorana neutrinosMajorana neutrinos , SUSY neutralinosSUSY neutralinos , etc. can couple to the SM Higgs boson and thus can enhance the Higgs invisible yield with respect to the SM predictions. In addition, the measurement of Higgs invisible branching ratio (BR) for the Higgs mass of 125.5 GeV would provide a crucial scrutiny to the tiny SM predictions ( 10 ). In this article ATLAS and CMS searches for anomalous Higgs invisible decays are summarized
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
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
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