8,969 research outputs found
The Phillips - Barger model for the elastic cross section and the Odderon
Inspired by the recent TOTEM data for the elastic proton -- proton ()
scattering at 8 and 13 TeV, we update previous studies of the
differential cross sections using the Phillips -- Barger (PB) model, which
parametrizes the amplitude in terms of a small number of free parameters. We
demonstrate that this model is able to describe the recent data on a
statistically acceptable way. Additionally, we perform separate fits of the
data for each center - of - mass energy and propose a parametrization for
the energy dependence of the parameters present in the PB model. As a
consequence, we are able to present the PB predictions for the elastic proton -
proton cross section at GeV and TeV, which are compared
with the existing antiproton -- proton () data. We show that the PB
predictions, constrained by the data, are not able to describe the
data. In particular, the PB model predicts a dip in the differential
cross section that is not present in the data. Such result suggests
the contribution of the Odderon exchange at high energies.Comment: 6 pages, 4 tables, 2 figures, results updated, matches published
versio
The "red shelf" of the Hb line in the Seyfert 1 galaxies RXS J01177+3637 and HS 0328+05
A few Seyfert 1s have a Hb profile with a red wing usually called the "red
shelf". The most popular interpretation of this feature is that it is due to
broad redshifted lines of Hb and [OIII]4959,5007; we have observed two Seyfert
1s displaying a "red shelf" and showed that in these two objects the main
contributor is most probably the HeI 4922,5016 lines having the velocity and
width of the broad Hb component. There is no evidence for the presence of a
broad redshifted component of Hb or [OIII] in any of these two objects.Comment: LaTeX file (uses AA vers. 5.1 class, enclosed), 8 pages, 9 figures.
Accepted for publication in Astronomy & Astrophysics. Also available at
http://www.obs-hp.fr/www/preprints.htm
Axioms for the coincidence index of maps between manifolds of the same dimension
We study the coincidence theory of maps between two manifolds of the same
dimension from an axiomatic viewpoint. First we look at coincidences of maps
between manifolds where one of the maps is orientation true, and give a set of
axioms such that characterizes the local index (which is an integer valued
function). Then we consider coincidence theory for arbitrary pairs of maps
between two manifolds. Similarly we provide a set of axioms which characterize
the local index, which in this case is a function with values in . We also show in each setting that the group of values for the index
(either or ) is determined by the axioms.
Finally, for the general case of coincidence theory for arbitrary pairs of
maps between two manifolds we provide a set of axioms which charaterize the
local Reidemeister trace which is an element of an abelian group which depends
on the pair of functions. These results extend known results for coincidences
between orientable differentiable manifolds.Comment: 29 page
Inelastic quarkonium photoproduction in coherent hadron - hadron interactions at LHC energies
In this paper we study the inelastic quarkonium photoproduction in coherent
interactions. Considering the ultra relativistic hadrons as a
source of photons, we estimate the total ( and ) cross sections and rapidity distributions at
LHC energies. Our results demonstrate that the experimental analysis of this
process can be used to understand the underlying mechanism governing heavy
quarkonium production.Comment: 9 pages, 7 figures, 3 table
Miscellaneous observations of active galactic nuclei. II
We observed 37 AGN candidates and classified them on the basis of their
spectroscopic properties; three are confirmed QSOs, one is a BL Lac object,
nine are Seyfert 1 galaxies, four Seyfert 2s, while twenty are HII regions.Comment: LaTeX 2e, 15 pages (4 tables and 9 .eps figures included in text).
Uses L-AA 3.0, epsf.tex and psfig.sty (not included). Accepted to appear in
A&
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