1,427 research outputs found
Stabilization of internal space in noncommutative multidimensional cosmology
We study the cosmological aspects of a noncommutative, multidimensional
universe where the matter source is assumed to be a scalar field which does not
commute with the internal scale factor. We show that such noncommutativity
results in the internal dimensions being stabilizedComment: 8 pages, 1 figure, to appear in IJMP
Horizon Problem Remediation via Deformed Phase Space
We investigate the effects of a special kind of dynamical deformation between
the momenta of the scalar field of the Brans-Dicke theory and the scale factor
of the FRW metric. This special choice of deformation includes linearly a
deformation parameter. We trace the deformation footprints in the cosmological
equations of motion when the BD coupling parameter goes to infinity. One class
of the solutions gives a constant scale factor in the late time that confirms
the previous result obtained via another approach in the literature. This
effect can be interpreted as a quantum gravity footprint in the coarse grained
explanation. The another class of the solutions removes the big bang
singularity, and the accelerating expansion region has an infinite temporal
range which overcomes the horizon problem. After this epoch, there is a
graceful exiting by which the universe enters in the radiation dominated era.Comment: 13 pages, 2 figures, to appear in GER
ESTIMATION OF HORSE LEG MUSCLES FORCE DURING JUMPING
The purpose of the present study was to estimate horses’ leg muscle forces in jump height during jumping a spread fence of different heights. A digital camcorder was used (25 Hz) along with Ulead Studio program in order to obtain time, muscle lengths at rest, compression, extension, jump distance, and various angles in horse’s legs data. The total jump distance and time of flight for each horse were measured with a precision of 10m and 10s respectively. Biomechanical formulae have been established in order to evaluate the muscles stiffness coefficients. Three groups of leg muscles; serratus ventralis, biceps brachii, and radial carpal extensor were considered in this study and their forces were successfully estimated
Semileptonic and nonleptonic decays in three--point QCD sum rules and factorization approach
We analyze the semileptonic transition with , in the framework of the three--point QCD sum rules and the nonleptonic
decay within the QCD factorization approach. We study to
and transition form factors by separating the mixture
of the and states. Using the transition form factors of
the , we analyze the nonleptonic decay. We also
present the decay amplitude and decay width of these decays in terms of the
transition form factors. The branching ratios of these channel modes are also
calculated at different values of the mixing angle and compared
with the existing experimental data for the nonleptonic case.Comment: 28 Pages, 20 Figures and 9 Table
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