2,752 research outputs found

    Searches for new physics in top events at the Tevatron

    Full text link
    During the past years the CDF and D0 detectors have collected large amounts of data obtaining a relatively pure sample of pair-produced top quarks and a well understood sample containing singly-produced top quarks. These samples have been used for the precise measurement of the top quark properties, and have set stringent limits on new physics in the top sample. This reports presents the latest results from the CDF and D0 collaborations on the search for new physics within the top sample using an integrated data sample of up to 3.6 fb-1.Comment: Proceedings for the Moriond 2009 QCD sessio

    Exploring the Doubly Charged Higgs of the Left-Right Symmetric Model using Vector Boson Fusion-like Events at the LHC

    Get PDF
    This paper studies the pair production of the doubly charged Higgs boson of the left-right symmetric models using multilepton final state in the vector boson fusion (VBF)-like processes. The study is performed in the framework consistent with the model's correction to the standard model ρEW\rho_{EW} parameter. VBF topological cuts, number of leptons in the final state and pTp_T cuts on the leptons are found to be effective in suppressing the background. Significant mass reach can be achieved for exclusion/discovery of the doubly charge Higgs boson for the upcoming LHC run with a luminosity of O(103)\mathcal{O}(10^3) fb1^{-1}.Comment: 13 pages, 8 figures, 2 tables; Version 2:Journal matched versio

    Bottom-quark fusion processes at the LHC for probing \u3ci\u3eZ\u27\u3c/i\u3e models and \u3ci\u3eB\u3c/i\u3e-meson decay anomalies

    Get PDF
    We investigate models of a heavy neutral gauge boson Z\u27 coupling mostly to third generation quarks and second generation leptons. In this scenario, bottom quarks arising from gluon splitting can fuse into Z\u27 allowing the LHC to probe it. In the generic framework presented, anomalies in B-meson decays reported by the LHCb experiment imply a flavor-violating bs coupling of the featured Z\u27 constraining the lowest possible production cross section. A novel approach searching for a Z\u27(→ μμ) in association with at least one bottom-tagged jet can probe regions of model parameter space existing analyses are not sensitive to

    Bottom-quark fusion processes at the LHC for probing \u3ci\u3eZ\u27\u3c/i\u3e models and \u3ci\u3eB\u3c/i\u3e-meson decay anomalies

    Get PDF
    We investigate models of a heavy neutral gauge boson Z\u27 coupling mostly to third generation quarks and second generation leptons. In this scenario, bottom quarks arising from gluon splitting can fuse into Z\u27 allowing the LHC to probe it. In the generic framework presented, anomalies in B-meson decays reported by the LHCb experiment imply a flavor-violating bs coupling of the featured Z\u27 constraining the lowest possible production cross section. A novel approach searching for a Z\u27(→ μμ) in association with at least one bottom-tagged jet can probe regions of model parameter space existing analyses are not sensitive to

    Calcitonin free oat-cell carcinoma of the thyroid gland

    Full text link
    Two cases of primary oat-cell carcinoma of thyroid, in a 63-year-old woman and a 73-year-old man, are described. Case 1 was a compound tumour with the oat-cell component merging with a papillary component. Both tumours, in addition to histological features consistent with oat-cell carcinoma, showed immunohistochemical positivity with anti-chromagranin A and anti-synaptophysin antisera. Negative results were obtained when anti-calcitonin and anti-thyroglobulin antisera were employed. Using in situ hybridization, chromogranin A and B messenger RNAs were localized with biotinylated oligonucleotide probes. In contrast, with in situ hybridization, no localization for calcitonin messenger RNA was seen using radioactive and biotinylated probes. It is concluded that these calcitonin-free, small-cell carcinomas should be considered separately from medullary thyroid carcinomas and be regarded as a distinct entity, probably the thyroid equivalent of oat-cell carcinomas of the lung.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47516/1/428_2005_Article_BF01600144.pd

    Charged Particle Tracking in Real-Time Using a Full-Mesh Data Delivery Architecture and Associative Memory Techniques

    Full text link
    We present a flexible and scalable approach to address the challenges of charged particle track reconstruction in real-time event filters (Level-1 triggers) in collider physics experiments. The method described here is based on a full-mesh architecture for data distribution and relies on the Associative Memory approach to implement a pattern recognition algorithm that quickly identifies and organizes hits associated to trajectories of particles originating from particle collisions. We describe a successful implementation of a demonstration system composed of several innovative hardware and algorithmic elements. The implementation of a full-size system relies on the assumption that an Associative Memory device with the sufficient pattern density becomes available in the future, either through a dedicated ASIC or a modern FPGA. We demonstrate excellent performance in terms of track reconstruction efficiency, purity, momentum resolution, and processing time measured with data from a simulated LHC-like tracking detector

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

    Get PDF
    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an