1,721,049 research outputs found
Discovery and mass spectroscopy via mixed Di-Boson production at the LHC in a 4-Site model with a composite Higgs Boson
No full textWe investigate the scope of the Large Hadron Collider (LHC) in probing the parameter space of a 4-Site (4S) model supplemented by one composite Higgs state. We concentrate on the yield of 'mixed' di-boson production giving three leptons and missing (transverse) energy in the final state, i.e., events induced via the sub-process q\bar q' -> l^+\nu_l l^{'+}l^{'-} + , where are quarks and in all possible combinations, signature which enables the production in the intermediate steps of all additional -- with respect to the Standard Model (SM) -- neutral and charged gauge bosons belonging to the spectrum of this scenario, all of which in resonant topologies. We not only find this channel to be accessible over the background but also show that, after a dedicated cut-based analysis, kinematical reconstruction of all such resonances is always possible. We finally compare the yield of the mixed di-boson mode to that of the 'charged' di-boson one and find that the former is of lesser scope than the latter at smaller gauge boson masses but it overcomes it at higher values, thereby revealing itself a viable search mode covering new regions of parameter space
Drell-Yan production at the LHC in a four site Higgsless model
No full textWe consider a four site Higgsless model based on the SU(2)L × SU(2)1 × SU(2)2 × U(1)Y gauge symmetry, which predicts two neutral and four charged extra gauge bosons, Z1,2 and W±1,2. We compute the properties of the new particles, and derive indirect and direct limits on their masses and couplings from LEP and Tevatron data. In contrast to other Higgsless models, characterized by fermiophobic extra gauge bosons, here sizeable fermion-boson couplings are allowed by the electroweak precision data. The prospects of detecting the new predicted particles in the favoured Drell-Yan channel at the LHC are thus investigated. The outcome is that all six extra gauge bosons could be discovered in the early stage of the LHC low-luminosity run
A concrete composite 2-Higgs doublet model
No full textWe consider a Composite Higgs Model (CHM) with two isospin doublet Higgs fields arising as pseudo Nambu-Goldstone bosons from a SO(6) → SO(4) × SO(2) breaking. The main focus of this work is to explicitly compute the properties of these Higgses in terms of the fundamental parameters of the composite sector such as masses, Yukawa and gauge couplings of the new spin-1 and spin-1/2 resonances. Concretely, we calculate the Higgs potential at one-loop level through the Coleman-Weinberg mechanism from the explicit breaking of the SO(6) global symmetry by the partial compositeness of fermions and gauge bosons. We derive then the phenomenological properties of the Higgs states and highlight the main signatures of this Composite 2-Higgs Doublet Model at the Large Hadron Collider, including modifications to the SM-like Higgs couplings as well as production and decay channels of heavier Higgs bosons. We also consider flavour bounds that are typical of CHMs with more than one Higgs doublet.</p
Supersymmetry versus compositeness: 2HDMs tell the story
No full textSupersymmetry and Compositeness are two prevalent paradigms providing both a solution to the hierarchy problem and a motivation for a light Higgs boson state. As the latter has now been found, its dynamics can hold the key to disentangle the two theories. An open door towards the solution is found in the context of 2-Higgs Doublet Models (2HDMs), which are necessary to Supersymmetry and natural within Compositeness in order to enable Electro-Weak Symmetry Breaking. We show how 2HDM spectra of masses and couplings accessible at the Large Hadron Collider may allow one to separate the two scenarios.</p
W' production at the LHC in the 4-site Higgsless model
No full textWe study the phenomenology of the 4-site Higgsless model, based on the SU(2)_L × SU(2)_1 × SU(2)_2 × U(1)_Y gauge symmetry, at present colliders. The model predicts the existence of two neutral and four charged extra gauge bosons, Z_(1,2) and W±. In this paper, we focus on the charged gauge sector. We first derive limits on W1,2-boson masses and couplings to SM fermions from direct searches at the Tevatron. We then estimate at the 7 TeV LHC the exclusion limits with the actual L=1 fb?1 and the discovery potential with the expected L=10 fb?1. In contrast to the minimal (or 3-site) Higgsless model which predicts almost fermiophobic extra gauge bosons, the next-to-minimal (or 4-site) Higgsless model recovers sizeable W_(1,2)-boson couplings to ordinary matter, expressing the non-fermiophobic multiresonance inner nature of extra-dimensional theories. Owing to this feature, we find that in one year from now the new heavy gauge bosons, W± , could be discovered in the final state with an electron and large missing transverse energy at the 7 TeV LHC for W1,2-boson masses in the TeV region, depending on model parameter
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Z? production at the LHC in the four-site Higgsless model
No full textWe study the phenomenology of the neutral gauge sector of the four-site Higgsless model, based on the SU(2)L×SU(2)1×SU(2)2×U(1)Y gauge symmetry, at present colliders. The model predicts the existence of two neutral and four charged extra gauge bosons, Z1,2 and W1,2±. We expand and update a previous study, by concentrating on the neutral sector. We derive new limits on Z1,2-boson masses and couplings from recent direct searches at the Tevatron. We moreover estimate the discovery potential at the Tevatron with a project luminosity L=10??fb-1, and at the 7 TeV LHC with L=1??fb-1. In contrast to other Higgsless theories characterized by almost fermiophobic extra gauge bosons, the four-site model allows sizable Z1,2-boson couplings to standard model fermions. Owing to this feature, we find that in the next 2 years the extra Z1,2 bosons could be discovered in the favored Drell-Yan channel at the 7 TeV LHC for Z1,2 masses in the TeV region, depending on model parameters.<br/
Variations on the Author
Get PDF“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
Get PDFWe 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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