5,595 research outputs found
The spin structure of the nucleon in light-cone quark models
The quark spin densities related to generalized parton distributions in
impact-parameter space and to transverse-momentum dependent parton
distributions are reviewed within a light-cone quark model, with focus on the
role of the different spin-spin and spin-orbit correlations of quarks.Results
for azimuthal spin asymmetries in semi-inclusive deep-inelastic scattering due
to T-even transverse-momentum dependent parton distributions are also
discussed.Comment: proceedings of the workshop "Recent Advances in Perturbative QCD and
Hadronic Physics", 20-25 July 2009, ECT*, Trento (Italy), in Honor of Prof.
Anatoly Efremov's 75th Birthday Celebration; also based on the talk given at
the workshop "Transverse Partonic Structure of Hadrons", 21-26 June 2009,
Yerevan (Armenia); to appear in Mod. Phys. Lett.
First order effects of production on the continuum theory of spherical electrostatic probes
First order effects of production on continuum theory of spherical Langmuir probes in infinite, homogeneous, slightly ionized, collision-dominated plasm
Normal subgroups of diffeomorphism and homeomorphism groups of R^n and other open manifolds
We determine all the normal subgroups of the group of C^r diffeomorphisms of
R^n, r = 1,2,...,infinity, except when r=n+1 or n=4, and also of the group of
homeomorphisms of R^n (r=0). We also study the group A_0 of diffeomorphisms of
an open manifold M that are isotopic to the identity. If M is the interior of a
compact manifold with nonempty boundary, then the quotient of A_0 by the normal
subgroup of diffeomorphisms that coincide with the identity near to a given end
e of M is simple.Comment: This version corrects an error regarding the diffeomorphism groups of
R^1, since the line has two ends, in contrast to higher dimension
Azimuthal spin asymmetries in light-cone constituent quark models
We present results for all leading-twist azimuthal spin asymmetries in
semi-inclusive lepton-nucleon deep-inelastic scattering due to T-even
transverse-momentum dependent parton distribution functions on the basis of a
light-cone constituent quark model. Attention is paid to discuss the range of
applicability of the model, especially with regard to the scale dependence of
the observables and the transverse-momentum dependence of the distributions. We
find good agreement with available experimental data and present predictions to
be further tested by future CLAS, COMPASS and HERMES data.Comment: 23 pages, 14 figures, 1 tabl
TMDs and Azimuthal Spin Asymmetries in a Light-Cone Quark Model
The main properties of the leading-twist transverse momentum dependent parton
distributions in a light-cone constituent quark model of the nucleon are
reviewed, with focus on the role of the spin-spin and spin-orbit correlations
of quarks. Results for azimuthal single spin asymmetries in semi-inclusive deep
inelastic scattering are also discussed.Comment: Proceedings of SPIN2008, 6-11 October 2008, Charlottesville, VA, US
Transverse momentum dependent parton distributions and azimuthal asymmetries in light-cone quark models
We review the information on the spin and orbital angular momentum structure
of the nucleon encoded in the T-even transverse momentum dependent parton
distributions within light-cone quark models. Model results for azimuthal spin
asymmetries in semi-inclusive lepton-nucleon deep-inelastic scattering are
discussed, showing a good agreement with available experimental data and
providing predictions to be further tested by future CLAS, COMPASS and HERMES
data.Comment: 6 pages, 4 figures; proceedings of the "XIII Workshop On High Energy
Spin Physics Dubna Spin 2009", 1-5 September 2009, Dubna, Russi
XYZ-polarisation analysis of diffuse magnetic neutron scattering from single crystals
Studies of diffuse magnetic scattering largely benefit from the use of a
multi-detector covering wide scattering angles. Therefore, the different
contributions to the diffuse scattering that originate from magnetic, nuclear
coherent, and nuclear spin-incoherent scattering can be separated by the
so-called XYZ-polarization analysis. In the past this method has been
successfully applied to the analysis of diffuse scattering by polycrystalline
samples of magnetic disordered materials. Single crystal studies that exploit
the vector properties of spin correlations are of particular interest for
furthering our understanding of frustration effects in magnetism. Based on the
symmetry properties of polarised scattering a suitable extension of the
conventional XYZ method has been derived, which allows for the complete
separation and the analysis of features of diffuse magnetic scattering from
single crystals.Comment: 6 pages 2 figures, revised as published, one Eq. removed, minor
corrections, typos correcte
- …