51,647 research outputs found
Quark-Antiquark-Gluon Jets in DIS Diffractive Dissociation
We study the diffractive production of jets with large transverse
momenta in the region of large diffractive masses (small ). Cross
sections for transverse and longitudinal photons are obtained in the leading
log 1/x_{\fP} and log approximation, keeping all powers in log
. We perform a numerical study and illustrate the angular
distribution of the three jets. We also estimate the integrated diffractive
three jet cross section and compare with the dijet cross section obtained
before.Comment: 28 pages (Latex), 20 figures (Postscript
A kT-dependent sea-quark density for the CASCADE Monte Carlo event generator
Parton-shower event generators that go beyond the collinear-ordering
approximation at small x have so far included only gluon and valence quark
channels at transverse momentum dependent level. We describe results of recent
work to include effects of the sea-quark distribution with explicit dependence
on the transverse quark-momentum.This sea-quark density is then applied to the
description of forward Z -production. The qq*->Z matrix element (with one
off-shell quark) is calculated in an explicit gauge invariant way, making use
of high energy factorization. The kT-factorized result has been implemented
into the CCFM Monte-Carlo CASCADE and a numerical comparison with the qg*->Zq
matrix element has been carried out.Comment: 4 pages, 4 figures, based on a talk given at the XXI Workshop on
Deep-Inelastic Scattering and Related Subjects, 11-15 April, Newport News,
Virginia (2011
Canonically Transformed Detectors Applied to the Classical Inverse Scattering Problem
The concept of measurement in classical scattering is interpreted as an
overlap of a particle packet with some area in phase space that describes the
detector. Considering that usually we record the passage of particles at some
point in space, a common detector is described e.g. for one-dimensional systems
as a narrow strip in phase space. We generalize this concept allowing this
strip to be transformed by some, possibly non-linear, canonical transformation,
introducing thus a canonically transformed detector. We show such detectors to
be useful in the context of the inverse scattering problem in situations where
recently discovered scattering echoes could not be seen without their help.
More relevant applications in quantum systems are suggested.Comment: 8 pages, 15 figures. Better figures can be found in the original
article, wich can be found in
http://www.sm.luth.se/~norbert/home_journal/electronic/v12s1.html Related
movies can be found in www.cicc.unam.mx/~mau
Parton shower contributions to jets from high rapidities at the LHC
We discuss current issues associated with the dependence of jet distributions
at the LHC on the behavior of QCD parton showers for high rapidities.Comment: Contribution at DIS2012, Univ. of Bonn, March 201
Light Quark Mass Reweighting
We present a systematic study of the effectiveness of light quark mass
reweighting. This method allows a single lattice QCD ensemble, generated with a
specific value of the dynamical light quark mass, to be used to determine
results for other, nearby light dynamical quark masses. We study two gauge
field ensembles generated with 2+1 flavors of dynamical domain wall fermions
with light quark masses m_l=0.02 (m_\pi=620 MeV) and m_l=0.01 (m_\pi=420 MeV).
We reweight each ensemble to determine results which could be computed directly
from the other and check the consistency of the reweighted results with the
direct results. The large difference between the 0.02 and 0.01 light quark
masses suggests that this is an aggressive application of reweighting as can be
seen from fluctuations in the magnitude of the reweighting factor by four
orders of magnitude. Never-the-less, a comparison of the reweighed topological
charge, average plaquette, residual mass, pion mass, pion decay constant, and
scalar correlator between these two ensembles shows agreement well described by
the statistical errors. The issues of the effective number of configurations
and finite sample size bias are discussed. An examination of the topological
charge distribution implies that it is more favorable to reweight from heavier
mass to lighter quark mass.Comment: 24 pages and 10 figure
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