929 research outputs found
On projective group properties of the pseudo-Riemannian space
We study the six-dimensional pseudo-Riemannian spaces with two time-like
coordinates that admit non-homothetic infinitesimal projective transformations.
The metrics are manifestly obtained and the projective group properties are
determined. We also find a generic defining of projective motion in the
6-dimensional rigid h-space.Comment: 4 pages, talk presented at the "Integrable Systems-2005", Prague,
200
From the exclusive photoproduction of heavy quarkonia at HERA to the EDDE at TeVatron and LHC
Exclusive photoproduction of heavy quarkonia at HERA is analyzed in the
framework of the Regge-eikonal approach together with the nonrelativistic bound
state formalism. Total and differential cross-sections for the process
are calculated. The model predicts
cross-sections of Exclusive Double Diffractive Events (EDDE) at TeVatron and
LHC.Comment: 14 pages, 6 figures, reference is adde
DVCS on the nucleon : study of the twist-3 effects
We estimate the size of the twist-3 effects on deeply virtual Compton
scattering (DVCS) observables, in the Wandzura-Wilczek approximation. We
present results in the valence region for the DVCS cross sections, charge
asymmetries and single spin asymmetries, to twist-3 accuracy.Comment: 20 pages, 6 figure
5-dimensional Quantum Gravity Effects in Exclusive Double Diffractive Events
The experimentally measurable effects related to extra dimensional gravity in
a RS-type brane world are estimated. Two options of the RS framework (namely,
with small and large curvature) are considered. It is shown that both can be
detected by the joint experiment of the CMS and TOTEM Collaborations at the
LHC.Comment: 11 pages, 6 figures, 4 tables, acknowledgments are adde
Hadron multiplicities in e+e- annihilation with heavy primary quarks
The multiple hadron production in the events induced by the heavy primary
quarks in annihilation is reconsidered with account of corrected
experimental data. New value for the multiplicity in events is
presented on the basis of pQCD estimates.Comment: 16 pages, 6 figures. Version accepted for publication in EPJ
Extension of near-wall domain decomposition to modeling flows with laminar-turbulent transition
Non-overlapping Domain Decomposition for Modeling Essentially Unsteady Near-wall Turbulent Flows
A next-to-leading order QCD analysis of deeply virtual Compton scattering amplitudes
We present a next-to-leading order (NLO) QCD analysis of unpolarized and
polarized deeply virtual Compton scattering (DVCS) amplitudes, for two
different input scenarios, in the scheme. We illustrate and discuss
the size of the NLO effects and the behavior of the amplitudes in skewedness,
, and photon virtuality, . In the unpolarized case, at fixed ,
we find a remarkable effective power-law behaviour in , akin to Regge
factorization, over several orders of magnitude in . We also quantify
the ratio of real to imaginary parts of the DVCS amplitudes and their
sensitivity to changes of the factorization scale.Comment: 12 pages, 12 figures, revtex, final version to be published in Phys.
Rev. D. Corrected error in MRSA' distribution and modified extraplation
behavior of GRSV00 distribution. Corrected error in +i\epsilon treatment.
Taking now correct sheaf of log. Errors in subtraction equations corrected.
Figures and results for affected imaginary part of NLO amplitude changed
accordingl
A next-to-leading order analysis of deeply virtual Compton scattering
We present a complete, next-to-leading-order (NLO), leading-twist QCD
analysis of deeply virtual Compton scattering (DVCS) observables, in the scheme, and in the kinematic ranges of the H1, ZEUS and HERMES
experiments. We use a modified form of Radyushkin's ansatz for the input model
for the generalized parton distributions. We present results for leading order
(LO) and NLO for representative observables and find that they compare
favourably to the available data.Comment: 5 pages, 2 figures, revtex, published version, we modify Radyushkin's
ansatz for the GPDs to correct for finite hadronic mass effects, and, using
the latest MRST PDFs, now agree with the H1 data (modified figs). Typo in
Eq.(3) correcte
Lower bounds for open charm and beauty contributions to F_2
On the basis of some peculiar scaling properties of the OPE coefficient
functions, we give the lower bounds for F_2^{c\bar{c}} and F_2^{b\bar{b}}
independently of the properties of the gluon density function. Predictions for
F_2^{b\bar{b}} within reach of HERA are made.Comment: 10 pages, 4 eps figures. Misprints are corrected and comment is
added. To appear in JHE
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