529 research outputs found

    SUSY GUT Model Building

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    I discuss an evolution of SUSY GUT model building, starting with the construction of 4d GUTs, to orbifold GUTs and finally to orbifold GUTs within the heterotic string. This evolution is an attempt to obtain realistic string models, perhaps relevant for the LHC. This review is in memory of the sudden loss of Julius Wess, a leader in the field, who will be sorely missed.Comment: 24 pages, 14 figures, lectures given at PiTP 2008, Institute for Advanced Study, Princeton, to be published in the European Physical Journal

    Fully supersymmetric CP violations in the kaon system

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    We show that, on the contrary to the usual claims, fully supersymmetric CP violations in the kaon system are possible through the gluino mediated flavor changing interactions. Both Ï”K\epsilon_K and Re(Ï”â€Č/Ï”K){\rm Re} (\epsilon' / \epsilon_K) can be accommodated for relatively large tan⁥ÎČ\tan\beta without any fine tunings or contradictions to the FCNC and EDM constraints.Comment: Contribution to the Proceedings of ICHEP2000, Osaka, 200

    Transverse Fresnel-Fizeau drag effects in strongly dispersive media

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    A light beam normally incident upon an uniformly moving dielectric medium is in general subject to bendings due to a transverse Fresnel-Fizeau light drag effect. In conventional dielectrics, the magnitude of this bending effect is very small and hard to detect. Yet, it can be dramatically enhanced in strongly dispersive media where slow group velocities in the m/s range have been recently observed taking advantage of the electromagnetically induced transparency (EIT) effect. In addition to the usual downstream drag that takes place for positive group velocities, we predict a significant anomalous upstream drag to occur for small and negative group velocities. Furthermore, for sufficiently fast speeds of the medium, higher order dispersion terms are found to play an important role and to be responsible for peculiar effects such as light propagation along curved paths and the restoration of the spatial coherence of an incident noisy beam. The physics underlying this new class of slow-light effects is thoroughly discussed

    B --> Phi K_S and Supersymmetry

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    The rare decay B --> Phi K_S is a well-known probe of physics beyond the Standard Model because it arises only through loop effects yet has the same time-dependent CP asymmetry as B --> Psi K_S. Motivated by recent data suggesting new physics in B --> Phi K_S, we look to supersymmetry for possible explanations, including contributions mediated by gluino loops and by Higgs bosons. Chirality-preserving LL and RR gluino contributions are generically small, unless gluinos and squarks masses are close to the current lower bounds. Higgs contributions are also too small to explain a large asymmetry if we impose the current upper limit on B(B_s --> mu mu). On the other hand, chirality-flipping LR and RL gluino contributions can provide sizable effects and while remaining consistent with related results in B --> Psi K_S, Delta M_s, B --> X_s gamma and other processes. We discuss how the LR and RL insertions can be distinguished using other observables, and we provide a string-based model and other estimates to show that the needed sizes of mass insertions are reasonable.Comment: 33 pages, 32 figures, Updated version for PRD. Includes discussions of other recent works on this topic. Added discussions & plots for gluino mass dependence and effects of theoretical uncertaintie

    Analysis of the doubly heavy baryons in the nuclear matter with the QCD sum rules

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    In this article, we study the doubly heavy baryon states Ξcc\Xi_{cc}, Ωcc\Omega_{cc}, Ξbb\Xi_{bb} and Ωbb\Omega_{bb} in the nuclear matter using the QCD sum rules, and derive three coupled QCD sum rules for the masses, vector self-energies and pole residues. The predictions for the mass-shifts in the nuclear matter ΔMΞcc=−1.11 GeV\Delta M_{\Xi_{cc}}=-1.11\,\rm{GeV}, ΔMΩcc=−0.33 GeV\Delta M_{\Omega_{cc}}=-0.33\,\rm{GeV}, ΔMΞbb=−3.37 GeV\Delta M_{\Xi_{bb}}=-3.37\,\rm{GeV} and ΔMΩbb=−1.05 GeV\Delta M_{\Omega_{bb}}=-1.05\,\rm{GeV} can be confronted with the experimental data in the future.Comment: 10 pages, 4 figure

    Non-Invasive Mouse Models of Post-Traumatic Osteoarthritis

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    SummaryAnimal models of osteoarthritis (OA) are essential tools for investigating the development of the disease on a more rapid timeline than human OA. Mice are particularly useful due to the plethora of genetically modified or inbred mouse strains available. The majority of available mouse models of OA use a joint injury or other acute insult to initiate joint degeneration, representing post-traumatic osteoarthritis (PTOA). However, no consensus exists on which injury methods are most translatable to human OA. Currently, surgical injury methods are most commonly used for studies of OA in mice; however, these methods may have confounding effects due to the surgical/invasive injury procedure itself, rather than the targeted joint injury. Non-invasive injury methods avoid this complication by mechanically inducing a joint injury externally, without breaking the skin or disrupting the joint. In this regard, non-invasive injury models may be crucial for investigating early adaptive processes initiated at the time of injury, and may be more representative of human OA in which injury is induced mechanically. A small number of non-invasive mouse models of PTOA have been described within the last few years, including intra-articular fracture of tibial subchondral bone, cyclic tibial compression loading of articular cartilage, and anterior cruciate ligament (ACL) rupture via tibial compression overload. This review describes the methods used to induce joint injury in each of these non-invasive models, and presents the findings of studies utilizing these models. Altogether, these non-invasive mouse models represent a unique and important spectrum of animal models for studying different aspects of PTOA

    Analysis of the ΛQ\Lambda_Q baryons in the nuclear matter with the QCD sum rules

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    In this article, we study the Λc\Lambda_c and Λb\Lambda_b baryons in the nuclear matter using the QCD sum rules, and obtain the in-medium masses MΛc∗=2.335 GeVM_{\Lambda_c}^*=2.335\,\rm{GeV}, MΛb∗=5.678 GeVM_{\Lambda_b}^*=5.678\,\rm{GeV}, the in-medium vector self-energies ÎŁvΛc=34 MeV\Sigma^{\Lambda_c}_v=34\,\rm{MeV}, ÎŁvΛb=32 MeV\Sigma^{\Lambda_b}_v=32\,\rm{MeV}, and the in-medium pole residues λΛc∗=0.021 GeV3\lambda_{\Lambda_c}^*=0.021\,\rm{GeV}^3, λΛb∗=0.026 GeV3\lambda_{\Lambda_b}^*=0.026\,\rm{GeV}^3. The mass-shifts are MΛc∗−MΛc=51 MeVM_{\Lambda_c}^*-M_{\Lambda_c}=51\,\rm{MeV} and MΛb∗−MΛb=60 MeVM_{\Lambda_b}^*-M_{\Lambda_b}=60\,\rm{MeV}, respectively.Comment: 7 pages, 8 figures, revised versio

    Novel metallic states at low temperatures

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    We present an overview of unconventional metallic states arising close to magnetic quantum critical points with a focus on d-electron systems. The applicability and potential breakdowns of traditional self-consistent field theories of such materials are discussed as well as related phenomena in other systems

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

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    Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02
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