1,720,959 research outputs found
Minimal E6 supersymmetric standard model
No full textWe propose a Minimal E6 Supersymmetric Standard Model (ME6SSM) which allows Planck scale unification, provides a solution to the ? problem and predicts a new Z'. Above the conventional GUT scale MGUT ~ 1016 GeV the gauge group corresponds to a left-right symmetric Supersymmetric Pati-Salam model, together with an additional U(1)? gauge group arising from an E6 gauge group broken near the Planck scale. Below MGUT the ME6SSM contains three reducible 27 representations of the Standard Model gauge group together with an additional U(1)X gauge group, consisting of a novel and non-trivial linear combination of U(1)? and two Pati-Salam generators, which is broken at the TeV scale by the same singlet which also generates the effective ? term, resulting in a new low energy Z' gauge boson. We discuss the phenomenology of the new Z' gauge boson in some detail
Exceptional supersymmetric standard models with non-abelian discrete family symmetry
No full textWe introduce a non-Abelian discrete ?27 family symmetry into the recently proposed classes of Exceptional Supersymmetric Standard Model (E6SSM) based on a broken E6 Grand Unified Theory (GUT) in order to solve the flavour problem in these models and in particular to account for tri-bimaximal neutrino mixing. We consider both the minimal version of the model (the ME6SSM) with gauge coupling unification at the string scale and the E6SSM broken via the Pati-Salam chain with gauge coupling unification at the conventional GUT scale. In both models there are low energy exotic colour triplets with couplings suppressed by the symmetries of the model, including the family symmetry. This leads to suppressed proton decay and long lived TeV mass colour triplet states with striking signatures at the LHC
Planck scale unification in a supersymmetric Standard Model
No full textWe show how gauge coupling unification near the Planck scale Mpnot, vert, similar1019 GeV can be achieved in the framework of supersymmetry, facilitating a full unification of all forces with gravity. Below the conventional GUT scale MGUTnot, vert, similar1016 GeV physics is described by a Supersymmetric Standard Model whose particle content is that of three complete 27 representations of the gauge group E6. Above the conventional GUT scale the gauge group corresponds to a left–right symmetric Supersymmetric Pati–Salam model, which may be regarded as a “surrogate SUSY GUT” with all the nice features of SO(10) but without proton decay or doublet–triplet splitting problems. At the TeV scale the extra exotic states may be discovered at the LHC, providing an observable footprint of an underlying E6 gauge group broken at the Planck scale. Assuming an additional low energy U(1)X gauge group, identified as a non-trivial combination of diagonal E6 generators, the ? problem of the MSSM can be resolved
Solving the flavour problem in supersymmetric standard models with three Higgs families
No full textAbstractWe show how a non-Abelian family symmetry Δ27 can be used to solve the flavour problem of supersymmetric Standard Models containing three Higgs families such as the Exceptional Supersymmetric Standard Model (E6SSM). The three 27-dimensional families of the E6SSM, including the three families of Higgs fields, transform in a triplet representation of the Δ27 family symmetry, allowing the family symmetry to commute with a possible high energy E6 symmetry. The Δ27 family symmetry here provides a high energy understanding of the Z2H symmetry of the E6SSM, which solves the flavour changing neutral current problem of the three families of Higgs fields. The main phenomenological predictions of the model are tri-bi-maximal mixing for leptons, two almost degenerate LSPs and two almost degenerate families of colour triplet D-fermions, providing a clear prediction for the LHC. In addition the model predicts PGBs with masses below the TeV scale, and possibly much lighter, which appears to be a quite general and robust prediction of all models based on the D-term vacuum alignment mechanism
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
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
- …
