493,740 research outputs found
Quantum Holonomies in (2+1)-Dimensional Gravity
We describe an approach to the quantisation of (2+1)-dimensional gravity with
topology R x T^2 and negative cosmological constant, which uses two quantum
holonomy matrices satisfying a q-commutation relation. Solutions of diagonal
and upper-triangular form are constructed, which in the latter case exhibit
additional, non-trivial internal relations for each holonomy matrix.
Representations are constructed and a group of transformations - a
quasi-modular group - which preserves this structure, is presented.Comment: 10 pages Latex no figure
Use of W-Boson Longitudinal-Transverse Interference in Top Quark Spin-Correlation Functions: II
This continuation of the derivation of general beam-referenced stage-two
spin-correlation functions is for the analysis of top-antitop pair-production
at the Tevatron and at the Large Hadron Collider. Both the gluon-production and
the quark-production contributions are included for the
charged-lepton-plus-jets reaction p p or p bar{p} --> t bar{t} --> (W^+ b)(W^-
bar{b}) --> (l^{+} nu b)(W^- bar{b}). There is a simple 4-angle beam-referenced
spin-correlation function for determination of the relative sign of, or for
measurement of a possible non-trivial phase between the two dominant helicity
amplitudes for t --> W^{+} b decay. There is an analogous function and tests
for bar{t} --> W^{-} bar{b} decay. This signature requires use of the (t
bar{t}) c.m.-energy of the hadronically decaying W-boson, or the kinematically
equivalent cosine of the polar-angle of W-boson emission in the anti-top (top)
decay frame. Spinors and their outer-products are constructed so that the
helicity-amplitude phase convention of Jacob & Wick can be used throughout for
the fixing of the signs associated with this large W-boson
longitudinal-transverse interference effect.Comment: Continuation of hep-ph/0506240 to include gluon-production
contribution; 3 "postscript" figures. Equation numbers as in
published-on-line EPJ
A hydrodynamic approach to the Bose-Glass transition
Nonlinear hydrodynamics is used to evaluate disorder-induced corrections to
the vortex liquid tilt modulus for finite screening length and arbitrary
disorder geometry. Explicit results for aligned columnar defects yield a
criterion for locating the Bose glass transition line at all fields.Comment: 8 pages, 2 figures. Contributed talk at the First ESF-Vortex Matter
Conference in Agia Pelagia, Crete, September 199
Zoological results of a tour in the far east : Polyzoa Entoprocta and Ctenostomata
The Polyzoa discussed or described in this paper are all from fresh or brackish water. The majority are from the Tale Sap in the north-eastern part of the Malay Peninsula} but a few come from the Tai-Hu in the Kiangsu Province of China. I have also included notes on one Indian form. The following species are to be considered: ENTOPROCTA. Chitaspis athleticus, gen. et sp. nov., from the Tale Sap. CTENOSTOMATA. Alcyonidium mytili, Dalyell, from Indian estuaries, etc. Triticella pediceltata (Alder), from the Tale Sap. Bowerbankiacaudata, Hincks, from the Tale Sap and Perak. Paludicella elongata, Leidy, from the Tai-Hu. Paludicella pentagonalis, sp. nov., from the Tale Sap. Victorelta bengalensis, Annandale, from the Tale Sap. Hislopia cambodgiensis (Jullien), from the Tai-Hu. Hislopia malayensis. sp. nov., from Jalor in the Malay Peninsula. It will be as well to defer consideration of the biology and distribution of these species until I have been able to deal systematically with the Phylactolaemata and Cheilostomata collected on my tour. All that need be said here is that while the species of Paludicella and Hislopia are from fresh water, the others. on the list are from brackish water
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