115 research outputs found
Extraction of the Ratio of the Neutron to Proton Structure Functions from Deep Inelastic Scattering
We study the nuclear () dependence of the European Muon Collaboration
(EMC) effect at high values of (). Our approach makes use of
conventional nuclear degrees of freedom within the Relativistic Impulse
Approximation. By performing a non-relativistic series expansion we demonstrate
that relativistic corrections make a substantial contribution to the effect at
and show that the ratio of neutron to proton structure
functions extracted from a global fit to all nuclei is not inconsistent with
values obtained from the deuteron.Comment: 12 pages, 2 figures available upon request, Revte
The Strong Coupling Constant from Hadron Structure Phenomenology
We present recent developments on the role of the running coupling constant
at the intersection of perturbative and nonperturbative QCD. A number of
experiments show a smooth transition from small to large scales given by the
four-momentum transfer in the reactions. This is at variance with perturbative
QCD where the running coupling constant becomes infinite when the scale equals
. Approaches using an effective coupling constant could
help interpret the opposite trend of data as compared to standard perturbative
QCD predictions. We give an overview of the role of the coupling constant in
the procedure to match nonperturbative hadronic model to perturbative QCD and
we propose an extraction of an effective coupling constant from inclusive
electron proton scattering data at large Bjorken x.Comment: To appear in the proceedings of the QCD Evolution Workshop, JLab, May
14-17, 2012. Includes ws-ijmpcs.cl
Deeply Virtual Exclusive Processes with Charm
We propose to investigate a largely unexplored sector that is unique to the
formulation of hard exclusive processes in terms of GPDs, namely the
electroproduction of strange and charmed mesons in the kinematical ranges of
Jefferson Lab's 12 GeV upgrade, and of the proposed Electron Ion Collider
(EIC). In this contribution we focus on charmed meson production that is unique
to the EIC. Exclusive strange and charmed meson production provides new
insights in the connection of the quark/gluon degrees of freedom with the
meson-baryon description, both in the unpolarized and polarized sectors.
However, as particularly evident in polarized scattering, the underlying
mechanisms are still far from being fully understood. We present an approach in
terms of generalized parton distributions. As an application, we show that
through exclusive electroproduction of pseudoscalar charmed mesons one can
uniquely single out the non-perturbative charmed component in the nucleon
structure function.Comment: 8 pages, 3 figures, to appear in proceedings of Workshop on Exclusive
Reactions at High Momentum Transfer (IV), Jefferson Lab, May 18-21, 201
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