139 research outputs found

    Higgs Boson Phenomenology in a Simple Model with Vector Resonances

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    In this paper we consider a simple scenario where the Higgs boson and two vector resonances are supposed to arise from a new strong interacting sector. We use the ATLAS measurements of the dijet spectrum to set limits on the masses of the resonances. Additionally we compute the Higgs boson decay to two photons and found, when compare to the Standard Model prediction, a small excess which is compatible with ATLAS measurements. Finally we make prediction for Higgs-strahlung processes for the LHC running at 14 TeV

    Search for sterile neutrinos decaying into pions at the LHC

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    We study the possibility to observe sterile neutrinos with masses in the range between 5 GeV and 20 GeV at the LHC, using the exclusive semileptonic modes involving pions, namely W to lepton + N to n pions + lepton+lepton (n = 1, 2, 3). The two pion and three pion modes require extrapolations of form factors to large time-like q2q^2, which we do using vector dominance models as well as light front holographic QCD, with remarkable agreement. This mass region is difficult to explore with inclusive dilepton+dijet modes or trilepton modes and impossible to explore in rare meson decays. While particle identification is a real challenge in these modes, vertex displacement due to the long living neutrino in the above mass range can greatly help reduce backgrounds. Assuming a sample of 10910^9 W bosons at the end of the LHC Run 2, these modes could discover a sterile neutrino in the above mass range or improve the current bounds on the heavy-to-light lepton mixings by an order of magnitude, UlN2∌2×10−6U_{l N}^2 \sim 2 \times 10^{-6}. Moreover, by studying the equal sign and opposite sign dileptons, the Majorana or Dirac character of the sterile neutrino may be revealed.Comment: 18 pages, 4 double figure

    Probing Neutrino Dirac Mass in Left-Right Symmetric Models at the LHC and Next Generation Colliders

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    We assess the sensitivity of the LHC, its high energy upgrade, and a prospective 100 TeV hadronic collider to the Dirac Yukawa coupling of the heavy neutrinos in left-right symmetric models (LRSMs). We focus specifically on the trilepton final state in regions of parameter space yielding prompt decays of the right-handed gauge bosons (WRW_R) and neutrinos (NRN_R). In the minimal LRSM, the Dirac Yukawa couplings are completely fixed in terms of the mass matrices for the heavy and light neutrinos. In this case, the trilepton signal provides a direct probe of the Dirac mass term for a fixed WRW_R and NRN_R mass. We find that while it is possible to discover the WRW_R at the LHC, probing the Dirac Yukawa couplings will require a 100 TeV pppp collider. We also show that the observation of the trilepton signal at the LHC would indicate the presence of a non-minimal LRSM scenario.Comment: 28 pages, 10 figures, references adde

    Towards a Cosmological Hubble Diagram for Type II-P Supernovae

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    We present the first high-redshift Hubble diagram for Type II-P supernovae (SNe II-P) based upon five events at redshift up to z~0.3. This diagram was constructed using photometry from the Canada-France-Hawaii Telescope Supernova Legacy Survey and absorption line spectroscopy from the Keck observatory. The method used to measure distances to these supernovae is based on recent work by Hamuy & Pinto (2002) and exploits a correlation between the absolute brightness of SNe II-P and the expansion velocities derived from the minimum of the Fe II 516.9 nm P-Cygni feature observed during the plateau phases. We present three refinements to this method which significantly improve the practicality of measuring the distances of SNe II-P at cosmologically interesting redshifts. These are an extinction correction measurement based on the V-I colors at day 50, a cross-correlation measurement for the expansion velocity and the ability to extrapolate such velocities accurately over almost the entire plateau phase. We apply this revised method to our dataset of high-redshift SNe II-P and find that the resulting Hubble diagram has a scatter of only 0.26 magnitudes, thus demonstrating the feasibility of measuring the expansion history, with present facilities, using a method independent of that based upon supernovae of Type Ia.Comment: 36 pages, 16 figures, accepted for publication in Ap

    LSST: from Science Drivers to Reference Design and Anticipated Data Products

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    (Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg2^2 field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5σ\sigma point-source depth in a single visit in rr will be ∌24.5\sim 24.5 (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg2^2 with ÎŽ<+34.5∘\delta<+34.5^\circ, and will be imaged multiple times in six bands, ugrizyugrizy, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg2^2 region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to r∌27.5r\sim27.5. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overvie

    CSF Tau phosphorylation at Thr205 is associated with loss of white matter integrity in autosomal dominant Alzheimer disease

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    BACKGROUND: Hyperphosphorylation of tau leads to conformational changes that destabilize microtubules and hinder axonal transport in Alzheimer\u27s disease (AD). However, it remains unknown whether white matter (WM) decline due to AD is associated with specific Tau phosphorylation site(s). METHODS: In autosomal dominant AD (ADAD) mutation carriers (MC) and non-carriers (NC) we compared cerebrospinal fluid (CSF) phosphorylation at tau sites (pT217, pT181, pS202, and pT205) and total tau with WM measures, as derived from diffusion tensor imaging (DTI), and cognition. A WM composite metric, derived from a principal component analysis, was used to identify spatial decline seen in ADAD. RESULTS: The WM composite explained over 70% of the variance in MC. WM regions that strongly contributed to the spatial topography were located in callosal and cingulate regions. Loss of integrity within the WM composite was strongly associated with AD progression in MC as defined by the estimated years to onset (EYO) and cognitive decline. A linear regression demonstrated that amyloid, gray matter atrophy and phosphorylation at CSF tau site pT205 each uniquely explained a reduction in the WM composite within MC that was independent of vascular changes (white matter hyperintensities), and age. Hyperphosphorylation of CSF tau at other sites and total tau did not significantly predict WM composite loss. CONCLUSIONS: We identified a site-specific relationship between CSF phosphorylated tau and WM decline within MC. The presence of both amyloid deposition and Tau phosphorylation at pT205 were associated with WM composite loss. These findings highlight a primary AD-specific mechanism for WM dysfunction that is tightly coupled to symptom manifestation and cognitive decline

    Cerebrospinal fluid proteomics define the natural history of autosomal dominant Alzheimer’s disease

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    Alzheimer’s disease (AD) pathology develops many years before the onset of cognitive symptoms. Two pathological processes—aggregation of the amyloid-ÎČ (AÎČ) peptide into plaques and the microtubule protein tau into neurofibrillary tangles (NFTs)—are hallmarks of the disease. However, other pathological brain processes are thought to be key disease mediators of AÎČ plaque and NFT pathology. How these additional pathologies evolve over the course of the disease is currently unknown. Here we show that proteomic measurements in autosomal dominant AD cerebrospinal fluid (CSF) linked to brain protein coexpression can be used to characterize the evolution of AD pathology over a timescale spanning six decades. SMOC1 and SPON1 proteins associated with AÎČ plaques were elevated in AD CSF nearly 30 years before the onset of symptoms, followed by changes in synaptic proteins, metabolic proteins, axonal proteins, inflammatory proteins and finally decreases in neurosecretory proteins. The proteome discriminated mutation carriers from noncarriers before symptom onset as well or better than AÎČ and tau measures. Our results highlight the multifaceted landscape of AD pathophysiology and its temporal evolution. Such knowledge will be critical for developing precision therapeutic interventions and biomarkers for AD beyond those associated with AÎČ and tau.Fil: Johnson, Erik C. B.. University of Emory; Estados UnidosFil: Bian, Shijia. University of Emory; Estados UnidosFil: Haque, Rafi U.. University of Emory; Estados UnidosFil: Carter, E. Kathleen. University of Emory; Estados UnidosFil: Watson, Caroline M.. University of Emory; Estados UnidosFil: Gordon, Brian A.. Washington University in St. Louis; Estados UnidosFil: Ping, Lingyan. University of Emory; Estados UnidosFil: Duong, Duc M.. University of Emory; Estados UnidosFil: Epstein, Michael P.. University of Emory; Estados UnidosFil: McDade, Eric. Washington University in St. Louis; Estados UnidosFil: BarthĂ©lemy, Nicolas R.. Washington University in St. Louis; Estados UnidosFil: Karch, Celeste M.. Washington University in St. Louis; Estados UnidosFil: Xiong, Chengjie. Washington University in St. Louis; Estados UnidosFil: Cruchaga, Carlos. Washington University in St. Louis; Estados UnidosFil: Perrin, Richard J.. Washington University in St. Louis; Estados UnidosFil: Wingo, Aliza P.. Washington University in St. Louis; Estados UnidosFil: Wingo, Thomas S.. University of Emory; Estados UnidosFil: Chhatwal, Jasmeer P.. Harvard Medical School; Estados UnidosFil: Day, Gregory S.. University of Emory; Estados UnidosFil: Noble, James M.. Harvard Medical School; Estados UnidosFil: Berman, Sarah B.. Mayo Clinic; Estados UnidosFil: Martins, Ralph. Edith Cowan University; AustraliaFil: Graff Radford, Neill R.. Univeristy of Pittsburgh. School of Medicine; Estados Unidos. Mayo Clinic; Estados UnidosFil: Surace, Ezequiel Ignacio. FundaciĂłn para la Lucha Contra las Enfermedades NeurolĂłgicas de la Infancia. Instituto de Investigaciones NeurolĂłgicas "RaĂșl Carrea"; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; ArgentinaFil: Ortiz, Ana Luisa Sosa. Washington University in St. Louis; Estados UnidosFil: Daniels, Alisha. Washington University in St. Louis; Estados UnidosFil: Courtney, Laura. Washington University in St. Louis; Estados UnidosFil: Supnet Bell, Charlene. Washington University in St. Louis; Estados UnidosFil: Xu, Jinbin. No especifĂ­ca;Fil: Ringman, John. No especifĂ­ca

    Insulin/IGF and Sex Hormone Axes in Human Endometrium and Associations with Endometrial Cancer Risk Factors

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    Given an ordered set of points and an ordered set of geometric objects in the plane, we are interested in finding a non-crossing matching between point-object pairs. In this paper, we address the algorithmic problem of determining whether a non-crossing matching exists between a given point-object pair. We show that when the objects we match the points to are finite point sets, the problem is NP-complete in general, and polynomial when the objects are on a line or when their size is at most 2. When the objects are line segments, we show that the problem is NP-complete in general, and polynomial when the segments form a convex polygon or are all on a line. Finally, for objects that are straight lines, we show that the problem of finding a min-max non-crossing matching is NP-complete. © 2012 Elsevier B.V.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
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