372 research outputs found
The Nuclear Emulsion Technology and the Analysis of the OPERA Experiment Data
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" Peccei-Quinn Symmetry
The Peccei-Quinn (PQ) solution to the strong problem requires an
anomalous global 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 PQ symmetry is virtually
embedded in a gauged 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
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- 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 -) TeV. We also construct a model of hidden strong gauge dynamics
which realizes the spin- 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
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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