754 research outputs found

    Pairs of charged heavy-leptons from an SU(3) X U(1) model at CERN LHC

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    One of the versions of the SU(3)_L\otimesU(1)_N electroweak model predicts charged heavy-leptons which do not belong to any class of heavy-leptons proposed up to now. We investigate the production and signatures of pairs of these heavy-leptons {\it via} the Drell-Yan process and the gluon-gluon fusion at the CERN Large Hadron Collider (LHC). As an example we study the decay of the exotic leptons into another ones. We see that the lifetime of the exotic leptons can be short.Comment: 12 pages, 8 figures, Revtex4, Version published in Nucl. Phys.

    Risk factors for incidence and persistence of disability in chronic major depression and alcohol use disorders: longitudinal analyses of a population-based study

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    BackgroundMajor depression and alcohol use disorders are risk factors for incidence of disability. However, it is still unclear whether a chronic course of these health conditions is also prospectively associated with incidence of disability. The aim of the present study was, first, to confirm whether chronic major depression (MD) and alcohol use disorders (AUD) are, respectively, risk factors for persistence and incidence of disability in the general population; and then to analyze the role of help-seeking behavior in the course of disability among respondents with chronic MD and chronic AUD. MethodData from two assessments in the National Epidemiologic Survey on Alcohol and Related Conditions were analyzed. Disability was measured by eight domains of the Short Form 12 Health Survey version 2 (SF-12). Generalized estimating equations and logistic regression models were run to estimate risk factors for persistence and incidence of disability, respectively. ResultsAnalyses conducted on data from the US general population showed that chronic MD was the strongest risk factor for incidence and persistence of disability in the social functioning, emotional role and mental health domains. Chronic AUD were risk factors for incidence and persistence of disability in the vitality, social functioning, and emotional role domains. Within the group of chronic MD, physical comorbidity and help-seeking were associated with persistent disability in most of the SF-12 domains. Help-seeking behavior was also associated with incidence of problems in the mental health domain for the depression group. Regarding the AUD group, comorbidity with physical health problems was a strong risk factor for persistence of disability in all SF-12 domains. Help-seeking behavior was not related to either persistence or incidence of disability in the chronic alcohol group. ConclusionsChronic MD and chronic AUD are independent risk factors for persistence and incidence of disability in the US general population. People with chronic MD seek help for their problems when they experience persistent disability, whereas people with chronic AUD might not seek any help even if they are suffering from persistent disability.<br/

    Pair of Heavy-Exotic-Quarks at LHC

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    We study the production and signatures of heavy exotic quarks pairs at LHC in the framework of the vector singlet model (VSM), vector doublet model (VDM) and fermion-mirror-fermion (FMF) model. The pair production cross sections for the electroweak and strong sector are computed.Comment: 7 pages, 6 figures. accept at Int. Jour. of Mod. Phy

    The ALMA Early Science View of FUor/EXor objects. III. The Slow and Wide Outflow of V883 Ori

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    We present Atacama Large Millimeter/ sub-millimeter Array (ALMA) observations of V883 Ori, an FU Ori object. We describe the molecular outflow and envelope of the system based on the 12^{12}CO and 13^{13}CO emissions, which together trace a bipolar molecular outflow. The C18^{18}O emission traces the rotational motion of the circumstellar disk. From the 12^{12}CO blue-shifted emission, we estimate a wide opening angle of \sim 150^{^{\circ}} for the outflow cavities. Also, we find that the outflow is very slow (characteristic velocity of only 0.65 km~s1^{-1}), which is unique for an FU Ori object. We calculate the kinematic properties of the outflow in the standard manner using the 12^{12}CO and 13^{13}CO emissions. In addition, we present a P Cygni profile observed in the high-resolution optical spectrum, evidence of a wind driven by the accretion and being the cause for the particular morphology of the outflows. We discuss the implications of our findings and the rise of these slow outflows during and/or after the formation of a rotationally supported disk.Comment: 12 pages, 7 figures, 2 tables. Accepte

    The Masses of Transition Circumstellar Disks: Observational Support for Photoevaporation Models

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    We report deep Sub-Millimeter Array observations of 26 pre-main-sequence (PMS) stars with evolved inner disks. These observations measure the mass of the outer disk (r ~20-100 AU) across every stage of the dissipation of the inner disk (r < 10 AU) as determined by the IR spectral energy distributions (SEDs). We find that only targets with high mid-IR excesses are detected and have disk masses in the 1-5 M_Jup range, while most of our objects remain undetected to sensitivity levels of M_DISK ~0.2-1.5 M_Jup. To put these results in a more general context, we collected publicly available data to construct the optical to millimeter wavelength SEDs of over 120 additional PMS stars. We find that the near-IR and mid-IR emission remain optically thick in objects whose disk masses span 2 orders of magnitude (~0.5-50 M_Jup). Taken together, these results imply that, in general, inner disks start to dissipate only after the outer disk has been significantly depleted of mass. This provides strong support for photoevaporation being one of the dominant processes driving disk evolution.Comment: Accepted for publication by ApJL, 4 pages and 3 figure

    Doubly charged Higgs from ee-γ\gamma scattering in the 3-3-1 Model

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    We studied the production and signatures of doubly charged Higgs bosons in the process γeHE+\gamma e^- \rightarrow H^{--}E^+, where E+E^+ is a heavy lepton, at the ee+e^-e^+ International Linear Collider (ILC) and CERN Linear Collider (CLIC). The intermediate photons are given by the Weizsa¨\ddot{a}cker-Williams and laser backscattering distributions. We found that significant signatures are obtained by bremsstrahlung and backward Comptom scattering of laser. A clear signal can be obtained for doubly charged Higgs bosons, doubly charged gauge bosons and heavy leptons

    Search for the Higgs Boson H20H_2^0 at LHC in 3-3-1 Model

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    We present an analysis of production and signature of neutral Higgs boson (H20H_{2}^{0}) on the version of the 3-3-1 model containing heavy leptons at the Large Hadron Collider. We studied the possibility to identify it using the respective branching ratios. Cross section are given for the collider energy, s=\sqrt{s} = 14 TeV. Event rates and significances are discussed for two possible values of integrated luminosity, 300 fb1^{-1} and 3000 fb1^{-1}.Comment: 17 pages 7 figures. arXiv admin note: substantial text overlap with arXiv:1205.404

    Probing doubly charged Higgs in e+ee^+ e^- Colliders in 3-3-1 Model

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    The SU(3)_L\otimesU(1)_N electroweak model predicts new Higgs bosons beyond the one of the standard model. In this work we investigate the signature and production of doubly charged Higgs bosons in the ee+e^-e^+ International Linear Collider and in the CERN Linear Collider. We compute the branching ratios for the doubly charged gauge bosons of the model.Comment: 17 pages, 12 figure
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