Mariana Carrillo-Gonzalez, Gabriel German, Alfredo Herrera-Aguilar
We show that proposed super-exponential warp factors of the form $e^{-2f} \sim e^{-2c_1e^{c_2 |\sigma|}}$, are not acceptable for a further reduction of the hierarchy problem because they lead to inconsistencies in the tachyonic braneworld models analysed. In particular, both the finiteness of the effective 4d Planck mass and the gravity localisation conditions, which can be stated by the requirement that $\int e^{-2f(\sigma)}d\sigma < \infty$, necessarily imply that both c_1 and c_2 should be positive. As a consequence the tachyonic field T turns out to be complex in contradiction with the real nature of the starting action for the tachyonic braneworld. We have analysed this situation for thin as well as thick tachyonic braneworlds with four--dimensional Poincare symmetry, for the case when a bulk cosmological constant is present, and even for a brane with an induced spatially flat four--dimensional cosmological background, and shown that in all cases the tachyon field T comes out to be inconsistently complex.
View original:
http://arxiv.org/abs/1210.0597
No comments:
Post a Comment