1,451 research outputs found
An off-shell I.R. regularization strategy in the analysis of collinear divergences
We present a method for the analysis of singularities of Feynman amplitudes
based on the Speer sector decomposition of the Schwinger parametric integrals
combined with the Mellin-Barnes transform. The sector decomposition method is
described in some details. We suggest the idea of applying the method to the
analysis of collinear singularities in inclusive QCD cross sections in the
mass-less limit regularizing the forward amplitudes by an off-shell choice of
the initial particle momenta. It is shown how the suggested strategy works in
the well known case of the one loop corrections to Deep Inelastic Scattering.Comment: 25 pages, 3 figure
2D kinematics of the edge-on spiral galaxy ESO 379-G006
We present a kinematical study of the nearly edge-on galaxy ESO 379-G006 that
shows the existence of extraplanar ionized gas. With Fabry-Perot spectroscopy
at H-alpha, we study the kinematics of ESO 379-G006 using velocity maps and
position-velocity diagrams parallel to the major and to the minor axis of the
galaxy. We build the rotation curve of the disk and discuss the role of
projection effects due to the fact of viewing this galaxy nearly edge-on. The
twisting of the isovelocities in the radial velocity field of the disk of ESO
379-G006 as well as the kinematic asymmetries found in some position-velocity
diagrams parallel to the minor axis of the galaxy suggest the existence of
deviations to circular motions in the disk that can be modeled and explained
with the inclusion of a radial inflow probably generated by a bar or by spiral
arms. We succeeded in detecting extraplanar Diffuse Ionized Gas in this galaxy.
At the same time, from the analysis of position-velocity diagrams, we found
some evidence that the extraplanar gas could lag in rotation velocity with
respect to the midplane rotation.Comment: 61 pages, 15 figures. Accepted for publication in A
- …