1,338 research outputs found
Charm and longitudinal structure functions with the Kharzeev-Levin-Nardi model
We use the Kharzeev-Levin-Nardi model of the low gluon distributions to
fit recent HERA data on charm and longitudinal structure functions. Having
checked that this model gives a good description of the data, we use it to
predict and to be measured in a future electron-ion collider. The
results interpolate between those obtained with the de Florian-Sassot and
Eskola-Paukkunen-Salgado nuclear gluon distributions. The conclusion of this
exercise is that the KLN model, simple as it is, may still be used as an
auxiliary tool to make estimates both for heavy ion and electron-ion
collisions.Comment: 6 pages, 7 figure
Nucleon Tensor Charge from Exclusive Electroproduction
Exclusive electroproduction from nucleons is suggested for extracting
the tensor charge and other quantities related to transversity from
experimental data. This process isolates C-parity odd and chiral odd
combinations of t-channel exchange quantum numbers. In a hadronic picture it
connects the meson production amplitudes to C-odd Regge exchanges with final
state interactions. In a description based on partonic degrees of freedom, the
helicity structure for this C-odd process relates to the quark helicity flip,
or chiral odd generalized parton distributions. This differs markedly from
deeply virtual Compton scattering, and both vector meson and charged
electroproduction, where the axial charge can enter the amplitudes. Contrarily
the tensor charge enters the process. The connection through the
helicity description of the process to both the partonic and hadronic
perspectives is studied and exploited in model calculations to indicate how the
tensor charge and other transversity parameters can be related to cross section
and spin asymmetry measurements over a broad range of kinematics.Comment: 40 pages, 14 figures Revised text clarifying main points, fixing
typos, adding reference
Bounds on R-parity Violation from Resonant Slepton Production at the LHC
We consider the ATLAS and CMS searches for dijet resonances, as well as the
ATLAS search for like-sign dimuon pairs at the LHC with 7 TeV center of mass
energy. We interpret their exclusions in terms of bounds on the supersymmetric
R-parity violating parameter space. For this we focus on resonant slepton
production followed by the corresponding decay.Comment: 17 pages, 11 figures, 3 table
On the dbar/ubar Asymmetry and Parton Distributions
We discuss the impact of different measurements of the dbar/ubar asymmetry in
the extraction of parameterizations of parton distribution functions.Comment: Contributed paper to LP01, 13 pages, 4 figure
Phenomenological description of the gamma* p cross section at low Q2
Low Q2 photon-proton cross sections are analysed using a simple,
QCD-motivated parametrisation ,
which gives a good description of the data. The Q2 dependence of the gamma* p
cross section is discussed in terms of the partonic transverse momenta of the
hadronic state the photon fluctuates into.Comment: 14 pages, revtex, epsfig, 2 figure
Design of Computer Experiments: a powerful tool for the numerical design of BAW filters
We apply Design of Computer Experiments methods to the simulation of piezoelectric stacks and the design of BAW resonators and filters. Through the example of DCS filters with two different technologies (Iridium and Molybdenum electrodes), we show that the definition and the exploitation of a metamodel can accurately replace acoustic simulations and allows therefore a much faster material stack desig
The Art academy without walls: photography in context.
A photographic workshop for the Art Academy Without Walls, Lusaka, Zambia 2004. A NORAD (Norwegian Government Aid Organisation) commissioned project to generate a photographic facility for the Zambian Visual Arts Community, carry out technical inductions, deliver daily thematic lectures and discussions, supervise thematic workshops, set up a public exhibition. Agree on a management strategy for the facility and write a report
Chi_1 and Polarisation Asymmetries for Quarkonia at High Orders in Non-relativistic QCD
We study doubly polarised asymmetries of c-cbar and b-bbar mesons in hadro-
and photo-production at low transverse momentum in non-relativistic QCD to high
orders in the relative velocity of the pair, v. We give the complete set of
expressions required for the asymmetries up to order v^9. The asymmetries in
the production of eta_{c,b} states are a stable measure of the polarised gluon
densities. The asymmetries for chi_{c,b}, J/psi, psi', and the various Upsilon
states are stringent tests of the NRQCD scaling relations.Comment: 21 pages LaTeX including 2 figure
Dynamical QCD Predictions for Ultrahigh Energy Neutrino Cross Sections
Neutrino-nucleon total cross sections for neutrino energies up to ultrahigh
energies (UHE), E_\nu=10^12 GeV, are evaluated within the framework of the
dynamical (radiative) parton model. The expected uncertainties of these
predictions do not exceed the level of about 20 % at the highest energies where
contributions of parton distributions in the yet unmeasured region around
x\simeq 10^-8 to 10^-9 are non-negligible. This is far more accurate than
estimated uncertainties of about 2^+-1 due to ad hoc extrapolations of parton
distributions to x<10^-5 required for calculating UHE cosmic neutrino event
rates.Comment: 16 pages, LaTeX, 4 figures, uses epsfig and amssymb styl
Spectroscopy at B-factories Using Hard Photon Emission
The process of hard photon emission by initial electrons (positrons) at
B-factories is discussed. It is shown that studies of the bottomonium
spectroscopy will be feasible for the planned integrated luminosity of the
B-factory experiments.Comment: 9 pages, Latex, 1 fugure, Submitted to Int.Jour.Mod.Phys.
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