372 research outputs found

    The Nuclear Emulsion Technology and the Analysis of the OPERA Experiment Data

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    OPERA is an experiment that aims at detecting the appearance of tau-neutrino in an almost pure mu-neutrino beam (the CNGS neutrino beam) through oscillation. OPERA is a hybrid detector that associates nuclear emulsions to electronic detectors. The nuclear emulsion provides the resolution necessary to detect tau-neutrino CC interactions. The first physics run started in July and ended in November 2008. In this presentation, the status of the emulsion technology and of the analysis of its data is reported.Comment: 6 pages, 16 Postscript figures, To be published in the proceedings of DPF-2009, Detroit, MI, July 2009, eConf C09072

    A "Gauged" U(1)U(1) Peccei-Quinn Symmetry

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    The Peccei-Quinn (PQ) solution to the strong CPCP problem requires an anomalous global U(1)U(1) symmetry, the PQ symmetry. The origin of such a convenient global symmetry is quite puzzling from the theoretical point of view in many aspects. In this paper, we propose a simple prescription which provides an origin of the PQ symmetry. There, the global U(1)U(1) PQ symmetry is virtually embedded in a gauged U(1)U(1) PQ symmetry. Due to its simplicity, this mechanism can be implemented in many conventional models with the PQ symmetry.Comment: 5 pages, 1 figure

    Diboson Resonance as a Portal to Hidden Strong Dynamics

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    We propose a new explanation for excess events observed in the search for a high-mass resonance decaying into dibosons by the ATLAS experiment. The resonance is identified as a composite spin-00 particle that couples to the Standard Model gauge bosons via dimension-5 operators. The excess events can be explained if the dimension-5 operators are suppressed by a mass scale of O(1{\cal O}(1-1010) TeV. We also construct a model of hidden strong gauge dynamics which realizes the spin-00 particle as its lightest composite state, with appropriate couplings to Standard Model gauge bosons.Comment: 21 pages, 4 figure

    Optional Synthesis of 2- or 5-Substituted 3-Bromopyrroles via Bromine-Lithium Exchange of N-Benzenesulfonyl-2,4-dibromopyrrole

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    The regioselective bromine–lithium exchange of N-benzenesulfonyl-2,4-dibromopyrrole (6) with n-BuLi followed by treatment with various electrophiles gave 5-substituted 3-bromopyrroles (5) in excellent yields. In contrast, the sequential treatment of 6 with n-BuLi and diisopropylamine followed by quenching with electrophiles produced regioisomeric 2-substituted 3-bromopyrroles (3) selectively. The latter reaction can be rationalized by the rapid equilibration of the C-5 lithio species (4) to the more stable C-2 lithio species (2) in the presence of diisopropylamine
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