Large-Q^2 behavior of the pion electromagnetic form factor

We study the large-Q^2 behavior of the electromagnetic form factor of the pion, which is viewed as a quark-antiquark bound state in a (nongauge) quantum field theory. When the pion's Bethe-Salpeter wave function is expanded in O(4) partial waves, it is found that the information needed about the partial-wave amplitudes is their scaling behavior at large momentum and the locations of their poles in the complex J plane. This information is determined by using the operator-product expansion, conformal invariance at short distances, and a regularity property that holds at least in the ladder model. The resulting behavior of the form factor is roughly F(Q^2)~(Q^2)^(-1), with corrections due to anomalous dimensions

The American Religious Landscape and the 2004 Presidential Vote: Increased Polarization

Presents findings from a post-election survey conducted in November and December 2004. Explores the polarization between different religions, as well as within the major religious traditions

Light-cone behavior of the pion Bethe-Salpeter wave function in the ladder model

The Bethe-Salpeter wave function χ(q^ν+P^ν, q^ν) for two spin-½ quarks bound by the exchange of a scalar meson is examined in the ladder model. We seek the behavior of χ as the squared momentum, (q+P)^2, on one leg becomes infinite while the squared momentum, q^2, on the other leg remains fixed. This behavior is investigated by making a Wick rotation, expanding χ in partial-wave amplitudes χ^i_J(q^2) of the group O(4), and then looking for the rightmost poles of χ^i_J(q^2) in the complex J plane. Our results verify (in the ladder model) the useful hypothesis that the locations of these poles are independent of q^2 and can thus be computed in the q^2→∞ limit by using conformal invariance

Extra force and extra mass from noncompact Kaluza-Klein theory in a cosmological model

Using the Hamilton-Jacobi formalism, we study extra force and extra mass in a recently introduced noncompact Kaluza-Klein cosmological model. We examine the inertial 4D mass $m_0$ of the inflaton field on a 4D FRW bulk in two examples. We find that $m_0$ has a geometrical origin and antigravitational effects on a non inertial 4D bulk should be a consequence of the motion of the fifth coordinate with respect to the 4D bulk.Comment: final version to be published in EPJ

Cosmological Surrealism: More than ``Eternal Reality" is Needed

Inflationary Cosmology makes the universe ``eternal" and provides for recurrent universe creation, ad infinitum -- making it also plausible to assume that ``our" Big Bang was also preceeded by others, etc.. However, GR tells us that in the ``parent" universe's reference frame, the newborn universe's expansion will never start. Our picture of ``reality" in spacetime has to be enlarged.Comment: 7 pages, TAUP N23

Origin of FRW cosmology in slow-roll inflation from noncompact Kaluza-Klein theory

Using a recently introduced formalism we discuss slow-roll inflaton from Kaluza-Klein theory without the cylinder condition. In particular, some examples corresponding to polynomic and hyperbolic $\phi$-potentials are studied. We find that the evolution of the fifth coordinate should be determinant for both, the evolution of the early inflationary universe and the quantum fluctuations.Comment: (final version) to be published in EPJ

Inflation without Slow Roll

We draw attention to the possibility that inflation (i.e. accelerated expansion) might continue after the end of slow roll, during a period of fast oscillations of the inflaton field \phi . This phenomenon takes place when a mild non-convexity inequality is satisfied by the potential V(\phi). The presence of such a period of \phi-oscillation-driven inflation can substantially modify reheating scenarios. In some models the effect of these fast oscillations might be imprinted on the primordial perturbation spectrum at cosmological scales.Comment: 9 pages, Revtex, psfig, 1 figure, minor modifications, references adde

Inhomogeneous scalar field solutions and inflation

We present new exact cosmological inhomogeneous solutions for gravity coupled to a scalar field in a general framework specified by the parameter $\lambda$. The equations of motion (and consequently the solutions) in this framework correspond either to low-energy string theory or Weyl integrable spacetime according to the sign of $\lambda$. We show that different inflationary behaviours are possible, as suggested by the study of the violation of the strong energy condition. Finally, by the analysis of certain curvature scalars we found that some of the solutions may be nonsingular.Comment: LaTex file, 14 page