12,308 research outputs found
Obtaining non-Abelian field theories via Faddeev-Jackiw symplectic formalism
In this work we have shown that it is possible to construct non-Abelian field
theories employing, in a systematic way, the Faddeev-Jackiw symplectic
formalism. This approach follows two steps. In the first step, the original
Abelian fields are modified in order to introduce the non-Abelian algebra.
After that, the Faddeev-Jackiw method is implemented and the gauge symmetry
relative to some non-Abelian symmetry group, is introduced through the
zero-mode of the symplectic matrix. We construct the SU(2) and SU(2)xU(1)
Yang-Mills theories having as starting point the U(1) Maxwell electromagnetic
theory.Comment: 6 pages. Revtex 4.
Six-dimensional weak-strong simulations of head-on beam-beam compensation in RHIC
To compensate the large beam-beam tune spread and beam-beam resonance driving
terms in the polarized proton operation in the Relativistic Heavy Ion Collider
(RHIC), we will introduce a low-energy DC electron beam into each ring to
collide head-on with the opposing proton beam. The device to provide the
electron beam is called an electron lens. In this article, using a 6-D
weak-strong-beam-beam interaction simulation model, we investigate the effects
of head-on beam-beam compensation with electron lenses on the proton beam
dynamics in the RHIC 250 GeV polarized proton operation. This article is
abridged from the published article [1].Comment: 5 pages, contribution to the ICFA Mini-Workshop on Beam-Beam Effects
in Hadron Colliders, CERN, Geneva, Switzerland, 18-22 Mar 201
Charmonium dissociation by mesons in heavy-ion collisions
The charmonium dissociation by mesons in relativistic heavy-ion reactions is
analyzed within the Regge approach. It is shown that the inclusion of the
initial and final state interactions in the dissociation of J/Psi to bar{D}* D*
close to threshold increases the cross section significantly and can not be
neglected in comparison to the total dissociation rate. This is due to resonant
bar{D}*-D* interactions in sqrt{s} close to the masses of the Psi(4.04) and
Psi(4.16) mesons. We also investigate thermal effects of the (c bar{c}) width
for such processes in the medium. All these effects change both the magnitude
and the shape of the cross section as a function of sqrt{s}. The results
obtained should be applied in the analysis of open and hidden charm production
in heavy-ion collisions.Comment: 4 pages, 2 figures; Talk given at ICTP 5th International Conference
on Perspectives in Hadronic Physics, Trieste, Italy, 22-26 May 200
A photometric analysis of Abell 1689: two-dimensional multi-structure decomposition, morphological classification, and the Fundamental Plane
We present a photometric analysis of 65 galaxies in the rich cluster Abell
1689 at , using the Hubble Space Telescope Advanced Camera for Surveys
archive images in the rest-frame -band. We perform two-dimensional
multi-component photometric decomposition of each galaxy adopting different
models of the surface-brightness distribution. We present an accurate
morphological classification for each of the sample galaxies. For 50 early-type
galaxies, we fit both a de Vaucouleurs and S\'ersic law; S0s are modelled by
also including a disc component described by an exponential law. Bars of SB0s
are described by the profile of a Ferrers ellipsoid. For the 15 spirals, we
model a S\'ersic bulge, exponential disc, and, when required, a Ferrers bar
component. We derive the Fundamental Plane by fitting 40 early-type galaxies in
the sample, using different surface-brightness distributions. We find that the
tightest plane is that derived by S\'ersic bulges. We find that bulges of
spirals lie on the same relation. The Fundamental Plane is better defined by
the bulges alone rather than the entire galaxies. Comparison with local samples
shows both an offset and rotation in the Fundamental Plane of Abell 1689.Comment: 53 pages, 71 figures, MNRAS in pres
A model-independent analysis of the dependence of the anomalous J/psi suppression on the number of participant nucleons
A recently published experimental dependence of the J/psi to Drell-Yan ratio
on the measured, by a zero degree calorimeter, forward energy E_ZDC in Pb+Pb
collisions at the CERN SPS is analyzed. Using a model-independent approach it
is shown that the data are at variance with an earlier published experimental
dependence of the same quantity on the transverse energy of neutral hadrons
E_T. The discrepancy is related to a moderate centrality region: 100 < N_p <
200 (N_p is the number of participant nucleons) and is peculiar only to the
data obtained within the `minimum bias' analysis (using the `theoretical
Drell-Yan'). This could result from systematic experimental errors in the
minimum bias sample. A possible source of the errors is discussed.Comment: 10 pages, LaTeX, 3 PS-figures. V2: Misprints are correcte
Lagrangian formulation for noncommutative nonlinear systems
In this work we use the well known formalism developed by Faddeev and Jackiw
to introduce noncommutativity within two nonlinear systems, the SU(2) Skyrme
and O(3) nonlinear sigma models. The final result is the Lagrangian
formulations for the noncommutative versions of both models. The possibility of
obtaining different noncommutative versions for these nonlinear systems is
demonstrated.Comment: 8 pages. Revex 4.
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