Dilaton Stabilization in Brane Gas Cosmology

Brane Gas Cosmology is an M-theory motivated attempt to reconcile aspects of the standard cosmology based on Einstein's theory of general relativity. Dilaton gravity, when incorporating winding p-brane states, has verified the Brandenberger--Vafa mechanism --a string-motivated conjecture which explains why only three of the nine spatial dimensions predicted by string theory grow large. Further investigation of this mechanism has argued for a hierarchy of subspaces, and has shown the internal directions to be stable to initial perturbations. These results, however, are dependent on a rolling dilaton, or varying strength of Newton's gravitational constant. In these proceedings we show that it is not possible to stabilize the dilaton and maintain the stability of the internal directions within the standard Brane Gas Cosmology setup.Comment: 6 pages, no figures. To appear in the Proceedings of MRST 2004, held at Concordia University, Montreal, QC, 12-14 May 200

Probing the gluon self-interaction in light mesons

We investigate masses and decay constants of light mesons from a coupled system of Dyson--Schwinger and Bethe--Salpeter equations. We explicitly take into account dominant non-Abelian contributions to the dressed quark-gluon vertex stemming from the gluon self-interaction. We construct the corresponding Bethe-Salpeter kernel that satisfies the axial-vector Ward-Takahashi identity. Our numerical treatment fully includes all momentum dependencies with all equations solved completely in the complex plane. This approach goes well beyond the rainbow-ladder approximation and permits us to investigate the influence of the gluon self-interaction on the properties of mesons. As a first result we find indications of a nonperturbative cancellation of the gluon self-interaction contributions and pion cloud effects in the mass of the rho-meson.Comment: 4 pages, 5 figures. Matches published version in PR

Beyond the rainbow: effects from pion back-coupling

We investigate hadronic unquenching effects in light quarks and mesons. To this end we take into account the back-coupling of the pion onto the quark propagator within the non-perturbative continuum framework of Schwinger-Dyson equations (SDE) and Bethe-Salpeter equations (BSE). We improve on a previous approach by explicitly solving both the coupled system of DSEs and BSEs in the complex plane and the normalisation problem for Bethe-Salpeter kernels depending on the total momentum of the meson. As a result of our study we find considerable unquenching effects in the spectrum of light pseudoscalar, vector and axial-vector mesons.Comment: 9 pages, 5 figures. Minor typos corrected. Version to appear in PR

Productivity of Federally Financed Research and Development Final Report, May 15, 1963 - May 14, 1966

Research project on federal and industrial patent acquisition and economic implications - NASA PROGRA

Grain marketing and National Competition Policy: reform or reaction?

Grain marketing arrangements in Australia have been controversial for many years. Following an account of the historical background to grain marketing, this article concentrates on more recent debates. The most interesting technical economic argument concerns the validity of claims that statutory marketing authorities with export monopoly powers can obtain higher prices. The article also discusses how marketing in Australia has been affected by Commonwealth and State Government policies with respect to microeconomic reform and privatization. Although major changes appear to have been made in grain marketing and its institutions, there are inherent economic problems with the current approach to deregulation.Crop Production/Industries, Marketing,