58,058 research outputs found
Simplicial minisuperspace models in the presence of a massive scalar field with arbitrary scalar coupling
We extend previous simplicial minisuperspace models to account for arbitrary
scalar coupling \eta R\phi^2.Comment: 24 pages and 9 figures. Accepted for publication by Classical and
Quantum Gravit
Anisotropic simplicial minisuperspace model
The computation of the simplicial minisuperspace wavefunction in the case of
anisotropic universes with a scalar matter field predicts the existence of a
large classical Lorentzian universe like our own at late timesComment: 19 pages, Latex, 6 figure
Irreversible processes and the accelerated-decelerated phases of the Universe
A model for the Universe is proposed where it is considered as a mixture of
scalar and matter fields. The particle production is due to an irreversible
transfer of energy from the gravitational field to the matter field and
represented by a non-equilibrium pressure. This model can simulate three
distinct periods of the Universe: (a) an accelerated epoch where the energy
density of the scalar field prevails over the matter field, (b) a past
decelerated period where the energy density of the matter field becomes more
predominant than the scalar energy density, and (c) a present acceleration
phase where the scalar energy density overcomes the energy density of the
matter field.Comment: 6 pages, 2 figures, to be published in Brazilian Journal of Physic
Meson decay in the Fock-Tani Formalism
The Fock-Tani formalism is a first principle method to obtain effective
interactions from microscopic Hamiltonians. Usually this formalism was applied
to scattering, here we introduced it to calculate partial decay widths for
mesons.Comment: Presented at HADRON05 XI. "International Conference on Hadron
Spectroscopy" Rio de Janeiro, Brazil, August 21 to 26, 200
Questing for Algebraic Mass Dimension One Spinor Fields
This work deals with new classes of spinors of mass dimension one in
Minkowski spacetime. In order to accomplish it, the Lounesto classification
scheme and the inversion theorem are going to be used. The algebraic framework
shall be revisited by explicating the central point performed by the Fierz
aggregate. Then the spinor classification is generalized in order to encompass
the new mass dimension one spinors. The spinor operator is shown to play a
prominent role to engender the new mass dimension one spinors, accordingly.Comment: 7 pages, final version to appear in Eur. Phys. J.
On the Nonrelativistic Limit of the phi^4 Theory in 2+1 Dimensions
We study the nonrelativistic limit of the quantum theory of a real scalar
field with quartic self-interaction. The two body scattering amplitude is
written in such way as to separate the contributions of high and low energy
intermediary states. From this result and the two loop computation of the self
energy correction, we determine an effective nonrelativistic action.Comment: 15 pages, 2 figures, revte
Testing SUSY models of lepton flavor violation at a photon collider
The loop level lepton flavor violating signals are studied in a scenario of
low-energy, R-parity conserving, supersymmetric seesaw mechanism within the
context of a high energy photon collider. Lepton flavor violation is due to off
diagonal elements in the left s-lepton mass matrix induced by renormalization
group equations. The average slepton masses and the off
diagonal matrix elements are treated as model independent free
phenomenological parameters in order to discover regions in the parameter space
where the signal cross section may be observable. At the energies of the
option of the future high-energy linear collider the signal has
a potentially large standard model background, and therefore particular
attention is paid to the study of kinematical cuts in order to reduce the
latter at an acceptable level. We find, for the () channel,
non-negligible fractions of the parameter space () where the statistical significance ()
is .Comment: 26 pages, 12 figures, Revtex
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