176,166 research outputs found
Faddeev-Skyrme Model and Rational Maps
The Faddeev-Skyrme model, a modified O(3) nonlinear sigma model in three
space dimensions, is known to admit topological solitons that are stabilized by
the Hopf charge. The Faddeev-Skyrme model is also related to the low-energy
limits of SU(2) Yang-Mills theory. Here, the model is reformulated into its
gauge-equivalent expression, which turns out to be Skyrme-like. The solitonic
solutions of this Skyrme-like model are analyzed by the rational map ansatz.
The energy function and the Bogomolny-type lower bound of the energy are
established. The generalized Faddeev-Skyrme model that originates from the
infrared limits of SU(N) Yang-Mills theory is presented.Comment: 12 pages, LaTex, minor typo correcte
Constraints on spacetime anisotropy and Lorentz violation from the GRAAL experiment
The GRAAL experiment could constrain the variations of the speed of light.
The anisotropy of the speed of light may imply that the spacetime is
anisotropic. Finsler geometry is a reasonable candidate to deal with the
spacetime anisotropy. In this paper, the Lorentz invariance violation (LIV) of
the photon sector is investigated in the locally Minkowski spacetime. The
locally Minkowski spacetime is a class of flat Finsler spacetime and refers a
metric with the anisotropic departure from the Minkowski one. The LIV matrices
used to fit the experimental data are represented in terms of these metric
deviations. The GRAAL experiment constrains the spacetime anisotropy to be less
than . In addition, we find that the simplest Finslerian photon
sector could be viewed as a geometric representation of the photon sector in
the minimal standard model extension (SME).Comment: 13 pages, 2 tables. Two typos are corrected in Table
BCVEGPY2.0: A upgrade version of the generator BCVEGPY with an addendum about hadroproduction of the -wave states
The generator BCVEGPY is upgraded by adding the hadroproduction of the
-wave excited states (denoted by or by and
) and by improving some features of the original one as well. We
denote it as BCVEGPY2.0. The -wave production is also calculated by taking
only the dominant gluon-gluon fusion mechanism (with the subprocess being dominated) into account as that for -wave. In
order to make the addendum piece of the upgraded generator as compact as
possible so as to increase its efficiency, we manipulate the amplitude as
compact as possible with FDC (a software for generating Feynman diagrams and
the algebra amplitudes, and for manipulating algebra formulae analytically etc)
and certain simplification techniques. The correctness of the program is tested
by checking the gauge invariance of the amplitude and by comparing the
numerical results with the existent ones in the literature carefully.Comment: 21 page, 4 figure
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