35 research outputs found

    TeV-scale bileptons, see-saw type II and lepton flavor violation in core-collapse supernova

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    Electrons and electron neutrinos in the inner core of the core-collapse supernova are highly degenerate and therefore numerous during a few seconds of explosion. In contrast, leptons of other flavors are non-degenerate and therefore relatively scarce. This is due to lepton flavor conservation. If this conservation law is broken by some non-standard interactions, electron neutrinos are converted to muon and tau-neutrinos, and electrons - to muons. This affects the supernova dynamics and the supernova neutrino signal. We consider lepton flavor violating interactions mediated by scalar bileptons, i.e. heavy scalars with lepton number 2. It is shown that in case of TeV-mass bileptons the electron fermi gas is equilibrated with non-electron species inside the inner supernova core at a time-scale of order of (1-100) ms. In particular, a scalar triplet which generates neutrino masses through the see-saw type II mechanism is considered. It is found that supernova core is sensitive to yet unprobed values of masses and couplings of the triplet.Comment: accepted to Eur.Phys.J.

    Solar Neutrino Masses and Mixing from Bilinear R-Parity Broken Supersymmetry: Analytical versus Numerical Results

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    We give an analytical calculation of solar neutrino masses and mixing at one-loop order within bilinear R-parity breaking supersymmetry, and compare our results to the exact numerical calculation. Our method is based on a systematic perturbative expansion of R-parity violating vertices to leading order. We find in general quite good agreement between approximate and full numerical calculation, but the approximate expressions are much simpler to implement. Our formalism works especially well for the case of the large mixing angle MSW solution (LMA-MSW), now strongly favoured by the recent KamLAND reactor neutrino data.Comment: 34 pages, 14 ps figs, some clarifying comments adde

    Applicability and Cost Implications for Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors Based on the ODYSSEY Outcomes Trial: Insights From the Department of Veterans Affairs

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    In the recently presented ODYSSEY Outcomes: Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab trial, alirocumab use in patients with acute coronary syndrome (ACS) and low-density lipoprotein cholesterol (LDL-C) ≥70 mg/dL (or non–high-density lipoprotein cholesterol ≥100 mg/dL or apolipoprotein B ≥80 mg/dL) resulted in a 15% relative (1.6% absolute) reduction in the risk of major adverse cardiovascular events. We evaluated what proportion of patients in the VA Health Care System would qualify for alirocumab on the basis of ODYSSEY Outcomes criteria, how they are currently treated with LDL-C–lowering medications, and the cost implications if other evidence-based medications were used first before a proprotein convertase subtilisin/kexin type 9 inhibitor was considered

    Very High-Risk ASCVD and Eligibility for Nonstatin Therapies Based on the 2018 AHA/ACC Cholesterol Guidelines

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    The 2018 American Heart Association/American College of Cardiology Multisociety Cholesterol Guidelines recommend risk stratification among patients with atherosclerotic cardiovascular disease (ASCVD) to identify “very high-risk ASCVD patients.” These patients have characteristics associated with a higher risk of recurrent ASCVD events; consequently, they derive a higher net absolute benefit from addition of ezetimibe and/or a proprotein convertase subtilisin/kexin type 9 inhibitor (PCSK9i) to statin therapy. From a clinical and payer’s perspective, we assessed the proportion of patients with ASCVD who will qualify as very high-risk based on the guideline criteria, their current lipid management, and how this will change with maximizing statin therapy and stepwise use of ezetimibe before consideration for a PCSK9i, as recommended by the 2018 cholesterol guideline

    Reconstructing Neutrino Properties from Collider Experiments in a Higgs Triplet Neutrino Mass Model

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    We extend the minimal supersymmetric standard model with bilinear R-parity violation to include a pair of Higgs triplet superfields. The neutral components of the Higgs triplets develop small vacuum expectation values (VEVs) quadratic in the bilinear R-parity breaking parameters. In this scheme the atmospheric neutrino mass scale arises from bilinear R-parity breaking while for reasonable values of parameters the solar neutrino mass scale is generated from the small Higgs triplet VEVs. We calculate neutrino masses and mixing angles in this model and show how the model can be tested at future colliders. The branching ratios of the doubly charged triplet decays are related to the solar neutrino angle via a simple formula.Comment: 19 pages, 4 figures; one formula corrected, two author's names corrected; some explanatory comments adde

    Top Squarks and Bottom Squarks in the MSSM with Complex Parameters

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    We present a phenomenological study of top squarks (~t_1,2) and bottom squarks (~b_1,2) in the Minimal Supersymmetric Standard Model (MSSM) with complex parameters A_t, A_b, \mu and M_1. In particular we focus on the CP phase dependence of the branching ratios of (~t_1,2) and (~b_1,2) decays. We give the formulae of the two-body decay widths and present numerical results. We find that the effect of the phases on the (~t_1,2) and (~b_1,2) decays can be quite significant in a large region of the MSSM parameter space. This could have important implications for (~t_1,2) and (~b_1,2) searches and the MSSM parameter determination in future collider experiments. We have also estimated the accuracy expected in the determination of the parameters of ~t_i and ~b_i by a global fit of the measured masses, decay branching ratios and production cross sections at e^+ e^- linear colliders with polarized beams. Analysing two scenarios, we find that the fundamental parameters apart from A_t and A_b can be determined with errors of 1% to 2%, assuming an integrated luminosity of 1 ab^-1 and a sufficiently large c.m.s. energy to produce also the heavier ~t_2 and ~b_2 states. The parameter A_t can be determined with an error of 2 - 3%, whereas the error on A_b is likely to be of the order of 50%.Comment: 31 pages, 8 figures, comments and references added, conclusions unchanged; version to appear in Phys. Rev.

    Search for charged Higgs bosons in top quark decays

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    We present a search for charged Higgs bosons in top quark decays. We analyze the \eplus, \muplus, eeee, eμe\mu, μμ\mu\mu, \etau and \mutau final states from top quark pair production events, using data from about 1fb1{\text{fb}}^{-1} of integrated luminosity recorded by the \dzero experiment at the Fermilab Tevatron Collider. We consider different scenarios of possible charged Higgs boson decays, one where the charged Higgs boson decays purely hadronically into a charm and a strange quark, another where it decays into a τ\tau lepton and a τ\tau neutrino and a third one where both decays appear. We extract limits on the branching ratio B(tH+b)B(t\to H^+ b) for all these models. We use two methods, one where the ttˉt\bar{t} production cross section is fixed, and one where the cross section is fitted simultaneously with B(tH+b)B(t\to H^+b). Based on the extracted limits, we exclude regions in the charged Higgs boson mass and tanβ\tan \beta parameter space for different scenarios of the minimal supersymmetric standard model.Comment: 10 pages, 8 figures, submitted to PL

    Supersymmetry beyond minimal flavour violation

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    We review the sources and phenomenology of non-minimal flavour violation in the MSSM. We discuss in some detail the most important theoretical and experimental constraints, as well as promising observables to look for supersymmetric effects at the LHC and in the future. We emphasize the sensitivity of flavour physics to the mechanism of supersymmetry breaking and to new degrees of freedom present at fundamental scales, such as the grand unification scale. We include a discussion of present data that may hint at departures from the Standard Model.Comment: 23pp. Version to appear in the EPJC special volume "Supersymmetry on the Eve of the LHC", dedicated to the memory of Julius Wess. References and brief discussion on collider signatures adde

    Search for Associated Production of Massive States Decaying into Two Photonsin e+e- Annihilations at sqrt(s) = 88-209 GeV

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    A search is performed for production of short-lived particles in e+e- -> XY, with X -> gamma gamma and Y -> ffbar, for scalar X and scalar or vector Y. Model-independent limits in the range of 25-60 femtobarns are presented on sigma (e+e- -> XY) x B(X -> ffbar) for centre-of-mass energies in the range 205-207 GeV. The data from all LEP centre-of-mass energies 88-209 GeV are also interpreted in the context of fermiophobic Higgs boson models, for which a lower mass limit of 105.5 GeV is obtained for a "benchmark" fermiophobic Higgs boson.Comment: 17 pages, 4 figure

    Collider aspects of flavour physics at high Q

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    This review presents flavour related issues in the production and decays of heavy states at LHC, both from the experimental side and from the theoretical side. We review top quark physics and discuss flavour aspects of several extensions of the Standard Model, such as supersymmetry, little Higgs model or models with extra dimensions. This includes discovery aspects as well as measurement of several properties of these heavy states. We also present public available computational tools related to this topic.Comment: Report of Working Group 1 of the CERN Workshop ``Flavour in the era of the LHC'', Geneva, Switzerland, November 2005 -- March 200
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