264 research outputs found
Single Transverse Spin Asymmetries in Semi-inclusive Deep Inelastic Scattering in a Spin-1 Diquark Model
The observed results for the azimuthal single spin asymmetries (SSAs) of the
proton, measured in the semi-inclusive deep inelastic scattering (SIDIS), can
be explained by the final-state interaction (FSI) from the gluon exchange
between the outgoing quark and the target spectator system. SSAs require a
phase difference between two amplitudes coupling the target with opposite spins
to the same final state. We have used the model of light front wave functions
(LFWFs) consisting of a spin- system as a composite of a
spin- fermion and a spin-1 vector boson to estimate the SSAs. The
implications of such a model have been investigated in detail by considering
different coupling constants. The FSIs also produce a complex phase which can
be included in the LFWFs to calculate the Sivers and Boer-Mulders distribution
functions of the nucleon.Comment: 23 pages, 4 figures. To appear in Eur. Phys. J.
Wigner distributions for an electron
We study the Wigner distributions for a physical electron, which reveal the
multidimensional images of the electron. The physical electron is considered as
a composite system of a bare electron and photon. The Wigner distributions for
unpolarized, longitudinally polarized and transversely polarized electron are
presented in transverse momentum plane as well as in impact parameter plane.
The spin-spin correlations between the bare electron and the physical electron
are discussed. We also evaluate all the leading twist generalized transverse
momentum distributions (GTMDs) for electron.Comment: 27 pages, 18 figures, text modified, version accepted in Nuclear
Physics
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Gravitational form factors and angular momentum densities in light-front quark-diquark model
We investigate the gravitational form factors (GFFs) and the longitudinal
momentum densities ( densities) for proton in a light-front quark-diquark
model. The light-front wave functions are constructed from the soft-wall
AdS/QCD prediction. The contributions from both the scalar and the axial vector
diquarks are considered here. The results are compared with the consequences of
a parametrization of nucleon generalized parton distributions (GPDs) in the
light of recent MRST measurements of parton distribution functions (PDFs) and a
soft-wall AdS/QCD model. The spatial distribution of angular momentum for up
and down quarks inside the nucleon has been presented. At the density level, we
illustrate different definitions of angular momentum explicitly for an up and
down quark in the light-front quark-diquark model inspired by AdS/QCD.Comment: 14 pages, 9 figures; version to appear in EPJ
Two Sample Statistical Test for Location Parameters
A class of distribution-free tests for the homogeneity of location parameters is proposed and compared with different competitors in terms of Pitman asymptotic relative efficiency. A numerical example is provided and a simulation study is made to check the performance of the tests
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