3,546 research outputs found
Hard Exclusive Electroproduction of Two Pions off Proton and Deuteron at HERMES
Exclusive electroproduction of pairs off hydrogen and deuterium
targets has been studied with the HERMES experiment. The angular distribution
of the in the rest system has been studied in the
invariant mass range GeV.
Theoretical models derived in the framework of the Generalized Parton
Distributions show that this angular distribution receives only contributions
from the interference between the isoscalar channel I=0 and the isovector
channel I=1.Comment: 5 pages, LaTex, 9 EPS figures. Talk given by R.Fabbri at SPIN 2002,
BNL. References modifie
Complex Monge-Amp\`ere equations on quasi-projective varieties
We introduce generalized Monge-Amp\`ere capacities and use these to study
complex Monge-Amp\`ere equations whose right-hand side is smooth outside a
divisor. We prove, in many cases, that there exists a unique normalized
solution which is smooth outside the divisor
Hitchhiker's guide to the fractional Sobolev spaces
This paper deals with the fractional Sobolev spaces W^[s,p]. We analyze the
relations among some of their possible definitions and their role in the trace
theory. We prove continuous and compact embeddings, investigating the problem
of the extension domains and other regularity results. Most of the results we
present here are probably well known to the experts, but we believe that our
proofs are original and we do not make use of any interpolation techniques nor
pass through the theory of Besov spaces. We also present some counterexamples
in non-Lipschitz domains
On the singularity type of full mass currents in big cohomology classes
Let be a compact K\"ahler manifold and be a big cohomology
class. We prove several results about the singularity type of full mass
currents, answering a number of open questions in the field. First, we show
that the Lelong numbers and multiplier ideal sheaves of
-plurisubharmonic functions with full mass are the same as those of the
current with minimal singularities. Second, given another big and nef class
, we show the inclusion Third, we characterize big classes whose full
mass currents are "additive". Our techniques make use of a characterization of
full mass currents in terms of the envelope of their singularity type. As an
essential ingredient we also develop the theory of weak geodesics in big
cohomology classes. Numerous applications of our results to complex geometry
are also given.Comment: v2. Theorem 1.1 updated to include statement about multiplier ideal
sheaves. Several typos fixed. v3. we make our arguments independent of the
regularity results of Berman-Demaill
L^1 metric geometry of big cohomology classes
Suppose is a compact K\"ahler manifold of dimension , and
is closed -form representing a big cohomology class. We
introduce a metric on the finite energy space ,
making it a complete geodesic metric space. This construction is potentially
more rigid compared to its analog from the K\"ahler case, as it only relies on
pluripotential theory, with no reference to infinite dimensional Finsler
geometry. Lastly, by adapting the results of Ross and Witt Nystr\"om to the big
case, we show that one can construct geodesic rays in this space in a flexible
manner
Nuclear p_t broadening at HERMES
The first direct measurement of p_t-broadening effects in cold nuclear matter
has been studied as a function of several kinematic variables for different
hadron types. The data have been accumulated by the HERMES experiment at DESY,
in which the HERA 27.6 GeV lepton beam scattered off several nuclear gas
targets.Comment: 4 pages, 5 figures, submitted to DIS 2007 proceeding
Finite Pluricomplex Energy Measures
We investigate probability measures with finite pluricomplex energy. We give
criteria insuring that a given measure has finite energy and test these on
various examples. We show that this notion is a biholomorphic but not a
bimeromorphic invariant
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