1,751 research outputs found

    Muon g-2 through a flavor structure on soft SUSY terms

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    In this work we analyze the possibility to explain the muon anomalous magnetic moment discrepancy within theory and experiment through lepton flavor violation processes. We propose a flavor extended MSSM by considering a hierarchical family structure for the trilinear scalar Soft-Supersymmetric terms of the Lagranagian, present at the SUSY breaking scale. We obtain analytical results for the rotation mass matrix, with the consequence of having non-universal slepton masses and the possibility of leptonic flavour mixing. The one-loop supersymmetric contributions to the leptonic flavour violating process τμγ\tau \to \mu\gamma are calculated in the physical basis, with slepton flavour mixed states, instead of using the well known Mass Insertion Method. We present the regions in parameter space where the muon g-2 problem is either entirely solved or partially reduced through the contribution of these flavor violating processes.Comment: 21 pages, 7 figures. Changes on version 3: In order to obtain the complete result for muon g-2 in the limit of non-flavor violation we added the terms given in the appendix. We redid the graphics and numerical analysis including these changes. We also corrected some typos and changed the order of figure

    Two-Higgs-Doublet type-II and -III models and tcht\to c h at the LHC

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    We study the constraints of the generic two-Higgs-doublet model (2HDM) type-III and the impacts of the new Yukawa couplings. For comparisons, we revisit the analysis in the 2HDM type-II. To understand the influence of all involving free parameters and to realize their correlations, we employ χ\chi-square fitting approach by including theoretical and experimental constraints, such as S, T, and U oblique parameters, the production of standard model Higgs and its decay to γγ\gamma\gamma, WW/ZZWW^*/ZZ^*, τ+τ\tau^+\tau^-, etc. The errors of analysis are taken at 68%68\%, 95.5%95.5\%, and 99.7%99.7\% confidence levels. Due to the new Yukawa couplings being associated with cos(βα)\cos(\beta-\alpha) and sin(βα)\sin(\beta -\alpha), we find that the allowed regions for sinα\sin\alpha and tanβ\tan\beta in the type-III model can be broader when the dictated parameter χF\chi_F is positive; however, for negative χF\chi_F, the limits are stricter than those in the type-II model. By using the constrained parameters, we find that the deviation from the SM in the hZγh\to Z\gamma can be of O(10%){\cal O}(10\%). Additionally, we also study the top-quark flavor-changing processes induced at the tree level in the type-III model and find that when all current experimental data are considered, we get Br(tc(h,H))<103Br(t\to c(h, H) )< 10^{-3} for mh=125.36m_h=125.36 and mH=150m_H=150 GeV and Br(tcA)Br(t\to cA) slightly exceeds 10310^{-3} for mA=130m_A =130 GeV.Comment: 22 pages, 11 figures. v3: Slight change in the abstract, Figure.1 added and commented, the conclusion remains unchange

    The dust morphology of the elliptical Galaxy M86 with SPIRE

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    We present Herschel-SPIRE observations at 250–500 μm of the giant elliptical galaxy M 86 and examine the distribution of the resolved cold dust emission and its relation with other galactic tracers. The SPIRE images reveal three dust components: emission from the central region; a dust lane extending north-south; and a bright emission feature 10 kpc to the south-east. We estimate that ~10^6 M_☉ of dust is spatially coincident with atomic and ionized hydrogen, originating from stripped material from the nearby spiral NGC 4438 due to recent tidal interactions with M 86. The gas-to-dust ratio of the cold gas component ranges from ~20–80. We discuss the different heating mechanisms for the dust features

    Concepts of Electroweak Symmetry Breaking and Higgs Physics

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    We present an introduction to the basic concepts of electroweak symmetry breaking and Higgs physics within the Standard Model and its supersymmetric extensions. A brief overview will also be given on alternative mechanisms of electroweak symmetry breaking. In addition to the theoretical basis, the present experimental status of Higgs physics and prospects at the Tevatron, the LHC and e+e- linear colliders are discussed

    Dependence on the Identification of the Scale Energy Parameter Q 2 in the Quark Distribution Functions for a DIS Production of Za

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    We discuss the Z-production in a DIS (Deep Inelastic Scattering) process e + p → e + Z + X using the Parton Model, within the context of the Standard Model. In contrast with deep inelastic eP-scattering (e + p → e + X), where the choice of Q2, as the transferred momentum squared, is unambiguous; whereas in the case of boson production , the transferred momentum squared, at quark level, depends on the reaction mechanism (where is the EW interaction taking place). We suggest a proposal based on kinematics of the process considered and the usual criterion for Q2 , which leads to a simple and practical prescription to calculate Z-production via ep-DIS. We also introduce different options in order o perform the convolution of the parton distribution functions (PDFs) and the scattering amplitude of he quark processes. Our aim in this work is to analyze and show how large could be the dependence of the total cross section rates on different possible prescriptions used for the identification of the scale energy parameter Q2 . We present results for the total cross section as a function of the total energy √s of the system ep, in the range 300 &lt;√s ≤ 1300 Ge

    MSSM Higgs Boson Production via Gluon Fusion: The Large Gluino Mass Limit

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    Scalar MSSM Higgs boson production via gluon fusion gg -> h,H is mediated by heavy quark and squark loops. The higher order QCD corrections to these processes turn out to be large. The full supersymmetric QCD corrections have been calculated recently. In the limit of large SUSY masses a conceptual problem appears, i.e. the proper treatment of the large gluino mass limit. In this work we will describe the consistent decoupling of heavy gluino effects and derive the effective Lagrangian for decoupled gluinos.Comment: 11 pages, 3 figures, latex, references added, slight rewording, version accepted by JHE

    Rompimiento de la Simetria Electrodebil y la Fisica del Higgs: Conceptos Basicos

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    Presentamos una introduccion a los conceptos basicos del rompimiento de la simetria electrodebil y la fisica del Higgs dentro del Modelo Estandar y sus extensiones supersimetricas. Se presenta tambien una breve perspectiva general de mecanismos alternativos del rompimiento de la simetria. Ademas de las bases teoricas, se discute el estado actual de la fisica experimental del Higgs y sus implicaciones para futuros experimentos en el LHC y en colisionadores lineales e+e-.Comment: Spanish text, including full English translation. Published in the Proceedings of the XI Mexican School on Particles and Fields, Xalapa, Veracruz, Mexic

    On the origin of M81 group extended dust emission

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    Galactic cirrus emission at far-infrared wavelengths affects many extragalactic observations. Separating this emission from that associated with extragalactic objects is both important and difficult. In this paper we discuss a particular case, the M81 group, and the identification of diffuse structures prominent in the infrared, but also detected at optical wavelengths. The origin of these structures has previously been controversial, ranging from them being the result of a past interaction between M81 and M82 or due to more local Galactic emission. We show that over an order of a few arcmin scales, the far-infrared (Herschel 250 mu m) emission correlates spatially very well with a particular narrow-velocity (2-3 km s(-1)) component of the Galactic HI. We find no evidence that any of the far-infrared emission associated with these features actually originates in the M81 group. Thus we infer that the associated diffuse optical emission must be due to galactic light-back scattered off dust in our galaxy. Ultraviolet observations pick out young stellar associations around M81, but no detectable far-infrared emission. We consider in detail one of the Galactic cirrus features, finding that the far-infrared HI relation breaks down below arcmin scales and that at smaller scales there can be quite large dust-temperature variation
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