479 research outputs found

    An alternative view on the electroweak interactions

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    We discuss an alternative to the Higgs mechanism which leads to gauge invariant masses for the electroweak bosons. The key idea is to reformulate the gauge invariance principle which, instead of being applied as usual at the level of the action, is applied at the level of the quantum fields. In other words, we define gauge invariant quantum fields which are used to build the action. In that framework, the Higgs field is not necessarily a physical degree of freedom but can merely be a dressing field that does not propagate. If the Higgs boson is not propagating, the weak interactions must become strongly coupled below 1 TeV and have a non-trivial fixed point and would thus be renormalizable at the non-perturbative level. On the other hand, if a gauge invariant Higgs boson is introduced in the model, its couplings to the fermions and the electroweak bosons can be quite different from those expected in the standard model.Comment: 10 page

    Koinonia

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    Empowerment Model, C.G. Kors Dilemma: New Age Infiltration, Dan Janosik NASPA + ACPA National Conventions Conference Speakers; Pre-Conference Workshopshttps://pillars.taylor.edu/acsd_koinonia/1054/thumbnail.jp

    Suppression of Higgsino mediated proton decay by cancellations in GUTs and strings

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    A mechanism for the enhancement for proton lifetime in supersymmetric/supergravity (SUSY/SUGRA) grand unified theories (GUTs) and in string theory models is discussed where Higgsino mediated proton decay arising from color triplets (anti-triplets) with charges Q=−1/3(1/3)Q=-1/3(1/3) and Q=−4/3(4/3)Q=-4/3(4/3) is suppressed by an internal cancellation due to contributions from different sources. We exhibit the mechanism for an SU(5) model with 45H+45ˉH45_H+\bar{45}_H Higgs multiplets in addition to the usual Higgs structure of the minimal model. This model contains both Q=−1/3(1/3)Q=-1/3(1/3) and Q=−4/3(4/3)Q=-4/3(4/3) Higgs color triplets (anti-triplets) and simple constraints allow for a complete suppression of Higgsino mediated proton decay. Suppression of proton decay in an SU(5) model with Planck scale contributions is also considered. The suppression mechanism is then exhibited for an SO(10) model with a unified Higgs structure involving 144H+144ˉH144_H+\bar{144}_H representations.The SU(5) decomposition of 144H+144ˉH144_H+\bar{144}_H contains 5H+5ˉH5_H+\bar 5_H and 45H+45ˉH45_H+\bar{45}_H and the cancellation mechanism arises among these contributions which mirrror the SU(5) case. The cancellation mechanism appears to be more generally valid for a larger class of unification models. Specifically the cancellation mechanism may play a role in string model constructions to suppress proton decay from dimension five operators. The mechanism allows for the suppression of proton decay consistent with current data allowing for the possibility that proton decay may be visible in the next round of nucleon stability experiment.Comment: 26 pages, no figures. Revtex 4. To appear in Physical Review

    Stuckelberg Axions and the Effective Action of Anomalous Abelian Models 1. A unitarity analysis of the Higgs-axion mixing

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    We analyze the quantum consistency of anomalous abelian models and of their effective field theories, rendered anomaly-free by a Wess-Zumino term, in the case of multiple abelian symmetries. These models involve the combined Higgs-Stuckelberg mechanism and predict a pseudoscalar axion-like field that mixes with the goldstones of the ordinary Higgs sector. We focus our study on the issue of unitarity of these models both before and after spontaneous symmetry breaking and detail the set of Ward identities and the organization of the loop expansion in the effective theory. The analysis is performed on simple models where we show, in general, the emergence of new effective vertices determined by certain anomalous interactions.Comment: 67 pages, 26 figures, replaced with revised final version, to appear on JHE

    High Scale Physics Connection to LHC Data

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    The existing data appears to provide hints of an underlying high scale theory. These arise from the gauge coupling unification, from the smallness of the neutrino masses, and via a non-vanishing muon anomaly. An overview of high scale models is given with a view to possible tests at the Large Hadron Collider. Specifically we discuss here some generic approaches to deciphering their signatures. We also consider an out of the box possibility of a four generation model where the fourth generation is a mirror generation rather than a sequential generation. Such a scenario can lead to some remarkably distinct signatures at the LHC.Comment: 23 pages, no figures. Based on invited lectures at the 46th Course at the International School of Subnuclear Physics- Erice -Sicily: 29 August -7 September, 200

    The Incidence of Trilateral Retinoblastoma : A Systematic Review and Meta-Analysis

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    PURPOSE: To estimate the incidence of trilateral retinoblastoma in patients with retinoblastoma. " DESIGN: Systematic review and meta-analysis. METHODS: We searched Medline and Embase for scientific literature published between January 1966 and July 2015 that assessed trilateral retinoblastoma incidence. We used a random-effects model for the statistical analyses. " RESULTS: We included 23 retinoblastoma cohorts from 26 studies. For patients with bilateral retinoblastoma the unadjusted chance of developing trilateral retinoblastoma across all cohorts was 5.3% (95% confidence interval [CI]: 3.3%-7.7%); the chance of pineal trilateral retinoblastoma was 4.2% (95% CI: 2.6%-6.2%) and the chance of nonpineal trilateral retinoblastoma was 0.8% (95% CI: 0.4%-1.3%). In patients with hereditary retinoblastoma (all bilateral cases, and the unilateral cases with a family history or germline RB1 mutation) we found a trilateral retinoblastoma incidence of 4.1% (95% CI: 1.9%-7.1%) and a pineal trilateral retinoblastoma incidence of 3.7% (95% CI: 1.8%-6.2%). To reduce the risk of overestimation bias we restricted analysis to retinoblastoma cohorts with a minimum size of 100 patients, resulting in adjusted incidences of 3.8% (95% CI: 2.4%-5.4%), 2.9% (95% CI: 1.9%-4.2%), and 0.7% (95% CI: 0.3%-1.2%) for any, pineal, and nonpineal trilateral retinoblastoma, respectively, among patients with bilateral retinoblastoma. Among hereditary retinoblastoma we found an adjusted trilateral retinoblastoma incidence of 3.5% (95% CI: 1.2%-6.7%) and a pineal trilateral retinoblastoma incidence of 3.2% (95% CI: 1.4%-5.6%). CONCLUSION: The estimated incidence of trilateral retinoblastoma is lower than what is reported in previous literature, especially after exclusion of small cohorts that were subject to overestimation bias in this context. (C) 2015 by Elsevier Inc. All rights reserved.)Peer reviewe

    Drug-induced atrial fibrillation

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    Atrial fibrillation (AF) is the most common sustained rhythm disorder observed in clinical practice and predominantly associated with cardiovascular disorders such as coronary heart disease and hypertension. However, several classes of drugs may induce AF in patients without apparent heart disease or may precipitate the onset of AF in patients with preexisting heart disease. We reviewed the literature on drug-induced AF, using the PubMed/Medline and Micromedex databases and lateral references. Successively, we discuss the potential role in the onset of AF of cardiovascular drugs, respiratory system drugs, cytostatics, central nervous system drugs, genitourinary system drugs, and some miscellaneous agents. Drug-induced AF may play a role in only a minority of the patients presenting with AF. Nevertheless, it is important to recognize drugs or other agents as a potential cause, especially in the elderly, because increasing age is associated with multiple drug use and a high incidence of AF. This may contribute to timely diagnosis and management of drug-induced AF

    D-term inflation in non-minimal supergravity

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    D-term inflation is one of the most interesting and versatile models of inflation. It is possible to implement naturally D-term inflation within high energy physics, as for example SUSY GUTs, SUGRA, or string theories. D-term inflation avoids the η\eta-problem, while in its standard form it always ends with the formation of cosmic strings. Given the recent three-year WMAP data on the cosmic microwave background temperature anisotropies, we examine whether D-term inflation can be successfully implemented in non-minimal supergravity theories. We show that for all our choices of K\"ahler potential, there exists a parameter space for which the predictions of D-term inflation are in agreement with the measurements. The cosmic string contribution on the measured temperature anisotropies is always dominant, unless the superpotential coupling constant is fine tuned; a result already obtained for D-term inflation within minimal supergravity. In conclusion, cosmic strings and their r\^ole in the angular power spectrum cannot be easily hidden by just considering a non-flat K\"ahler geometry.Comment: 29 pages, 9 figures; minor changes to match publihed versio

    Hunting long-lived gluinos at the Pierre Auger Observatory

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    Eventual signals of split sypersymmetry in cosmic ray physics are analyzed in detail. The study focusses particularly on quasi-stable colorless R-hadrons originating through confinement of long-lived gluinos (with quarks, anti-quarks, and gluons) produced in pp collisions at astrophysical sources. Because of parton density requirements, the gluino has a momentum which is considerable smaller than the energy of the primary proton, and so production of heavy (mass ~ 500 GeV) R-hadrons requires powerful cosmic ray engines able to accelerate particles up to extreme energies, somewhat above 10^{13.6} GeV. Using a realistic Monte Carlo simulation with the AIRES engine, we study the main characteristics of the air showers triggered when one of these exotic hadrons impinges on a stationary nucleon of the Earth atmosphere. We show that R-hadron air showers present clear differences with respect to those initiated by standard particles. We use this shower characteristics to construct observables which may be used to distinguish long-lived gluinos at the Pierre Auger Observatory.Comment: 13 pages revtex, 9 eps figures. A ps version with high resolution figures is available at http://www.hep.physics.neu.edu/staff/doqui/rhadron_highres.p

    Knowledge-based extraction of adverse drug events from biomedical text

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    Background: Many biomedical relation extraction systems are machine-learning based and have to be trained on large annotated corpora that are expensive and cumbersome to construct. We developed a knowledge-based relation extraction system that requires minimal training data, and applied the system for the extraction of adverse drug events from biomedical text. The system consists of a concept recognition module that identifies drugs and adverse effects in sentences, and a knowledg
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