2,656 research outputs found
Angular momentum sum rule in nuclei
In this work we derive a sum rule for the angular momentum of a spin 1
hadronic system.Comment: 5 pages, to appear in Proceedings of XVIII International Workshop on
Deep-Inelastic Scattering and Related Subjects, April 19 -23, 2010, Convitto
della Calza, Firenze, Ital
Microscopic Description of Deeply Virtual Compton Scattering off Spin-0 Nuclei
We evaluate within a microscopic calculation the contributions of both
coherent and incoherent deeply virtual Compton scattering from a spin-0
nucleus. The coherent contribution is obtained when the target nucleus recoils
as a whole, whereas for incoherent scattering break-up configurations for the
final nucleus into a an outgoing nucleon and an system are considered.
The two processes encode different characteristics of generalized parton
distributions.Comment: 7 pages, 3 figure
The impact of changing technology on the demand for air transportation
Demand models for air transportation that are sensitive to the impact of changing technology were developed. The models are responsive to potential changes in technology, and to changing economic, social, and political factors as well. In addition to anticipating the wide differences in the factors influencing the demand for long haul and short haul air travel, the models were designed to clearly distinguish among the unique features of these markets
Generalized Parton Distributions from Hadronic Observables
We propose a physically motivated parametrization for the unpolarized
generalized parton distributions, H and E, valid at both zero and non-zero
values of the skewness variable, \zeta. At \zeta=0, H and E are determined
using constraints from simultaneous fits of experimental data on both the
nucleon elastic form factors and the deep inelastic structure functions.
Lattice calculations of the higher moments constrain the parametrization at
\zeta > 0. Our method provides a step towards a model independent extraction of
generalized distributions from the data that is alternative to the mathematical
ansatz of double distributions.Comment: 4 pages, 2 figures, to appear in the proceedings of DIS 200
Angular momentum sum rule for spin one hadronic systems
We derive a sum rule for the total quark angular momentum of a spin-one
hadronic system within a gauge invariant decomposition of the hadron's spin. We
show that the total angular momentum can be measured through deeply virtual
Compton scattering experiments using transversely polarized deuteron targets.Comment: 4 pages, 2 figures, changes in text, figures changed, references
change
Nuclear Medium Modifications of Hadrons from Generalized Parton Distributions
We study the structure of generalized parton distributions in spin 0 nuclei
within a microscopic approach for nuclear dynamics. GPDs can be used on one
side as tools to unravel the deep inelastic transverse structure of nuclei in
terms of both transverse spatial and transverse momentum degrees of freedom. On
the other, one can obtain information on GPDs themselves by observing how they
become modified in the nuclear environment. We derive the structure of the
nuclear deeply virtual Compton scattering tensor and generalized parton
distributions at leading order in in a field-theoretical framework. The
nuclear generalized parton distributions are calculated using a two step
process -- the convolution approach -- where the scattering process happens
from a quark inside a nucleon, itself inside a nucleus, disregarding final
state interactions with both the nuclear and nucleon debris. We point out that
details of the nuclear long range interactions such as two-body currents, can
be disregarded compared to the deep inelastic induced modifications of the
bound GPDs. We show how the pattern of nuclear modifications predicted, and in
particular the deviations of off-shell effects from the longitudinal
convolution provide clear signals to be sought in experimental measurements.
Finally, we find interesting relationships by studying Mellin moments in
nuclei: in particular we predict the -dependence for the -term of GPDs
within a microscopic approach, and the behavior with of the total momentum
carried by quarks in a nucleus. The latter provides an important element for
the evaluation of nuclear hadronization phenomena which are vital for
interpreting current and future data at RHIC, HERMES and Jefferson Lab.Comment: 29 pages, 10 figure
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