4 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
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
Generalized Parton Distributions from Hadronic Observables: Zero Skewness
We propose a physically motivated parametrization for the unpolarized
generalized parton distributions. At zero value of the skewness variable,
, the parametrization is constrained by simultaneously fitting the
experimental data on both the nucleon elastic form factors and the deep
inelastic structure functions. A rich phenomenology can be addressed based on
this parametrization. In particular, we track the behavior of the average: {\it
i)} interparton distances as a function of the momentum fraction, , {\it
ii)} as a function of the four-momentum transfer, ; and {\it iii)} the
intrinsic transverse momentum as a function of . We discuss the
extension of our parametrization to where additional constraints
are provided by higher moments of the generalized parton distributions obtained
from {\it ab initio} lattice QCD calculations.Comment: 42 pages, 21 figure
Generalized Parton Distributions from Hadronic Observables: Non-Zero Skewness
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. Our approach follows a previous
detailed study of the \zeta=0 case where H and E were determined using
constraints from simultaneous fits of the experimental data on both the nucleon
elastic form factors and the deep inelastic structure functions in the non
singlet sector. Additional constraints at \zeta \neq 0 are provided by lattice
calculations of the higher moments of generalized parton distributions. We
illustrate a method for extracting generalized parton distributions from
lattice moments based on a reconstruction using sets of orthogonal polynomials.
The inclusion in our fit of data on Deeply Virtual Compton Scattering is also
discussed. Our method provides a step towards a model independent extraction of
generalized distributions from the data. It also provides an alternative to
double distributions based phenomenological models in that we are able to
satisfy the polynomiality condition by construction, using a combination of
experimental data and lattice, without resorting to any specific mathematical
construct.Comment: 29 pages, 8 figures; added references, changed text in several place