43,020 research outputs found
S-Duality and Brane Descent Relations
We present a description of the type IIB NS-NS p-branes in terms of
topological solitons in systems of spacetime-filling brane-antibrane pairs.
S-duality implies that these spacetime-filling branes are NS9-branes, S-dual to
the D9-branes of the type IIB theory. The possible vortex-like solutions in an
NS9,anti-NS9 configuration are identified by looking at its worldvolume
effective action. Finally we discuss the implications of these constructions in
the description of BPS and non-BPS states in the strongly coupled Heterotic
SO(32) theory.Comment: 14 pages, LaTeX file, no figures, final version to appear in JHE
The Descent Set and Connectivity Set of a Permutation
The descent set D(w) of a permutation w of 1,2,...,n is a standard and
well-studied statistic. We introduce a new statistic, the connectivity set
C(w), and show that it is a kind of dual object to D(w). The duality is stated
in terms of the inverse of a matrix that records the joint distribution of D(w)
and C(w). We also give a variation involving permutations of a multiset and a
q-analogue that keeps track of the number of inversions of w.Comment: 12 page
Three-particle correlations in QCD parton showers
Three-particle correlations in quark and gluon jets are computed for the
first time in perturbative QCD. We give results in the double logarithmic
approximation and the modified leading logarithmic approximation. In both
resummation schemes, we use the formalism of the generating functional and
solve the evolution equations analytically from the steepest descent evaluation
of the one-particle distribution. We thus provide a further test of the local
parton hadron duality and make predictions for the LHC.Comment: 9 pages and 5 figures. Version published by Physical Review D with
reference: Phys. Rev. D 84, 034015 (2011). Two more figures and one section
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Weight filtration on the cohomology of complex analytic spaces
We extend Deligne's weight filtration to the integer cohomology of complex
analytic spaces (endowed with an equivalence class of compactifications). In
general, the weight filtration that we obtain is not part of a mixed Hodge
structure. Our purely geometric proof is based on cubical descent for
resolution of singularities and Poincar\'e-Verdier duality. Using similar
techniques, we introduce the singularity filtration on the cohomology of
compactificable analytic spaces. This is a new and natural analytic invariant
which does not depend on the equivalence class of compactifications and is
related to the weight filtration.Comment: examples added + minor correction
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