Warped deformed throats have faster (electroweak) phase transitions

BABIKER HASSANAIN, JOHN MARCH-RUSSELL, MARTIN SCHVELLINGER

JOURNAL OF HIGH ENERGY PHYSICS - (Online)

SISSA

Lugar: Trieste - Italy; Año: 2007 vol. 10 p. 1 - 16

1029-8479

We study the dynamics of the finite-temperature phase transition for warped Randall-Sundrum(RS)-like throat models related to the Klebanov-Tseytlin solution. We find that, for infrared branes stabilized near the tip of the throat, the bounce action has a mild N2 dependence, where N(y) ~ [M5L(y)]3/2 is the effective number of degrees of freedom of the holographic dual QFT, and where L(y) is the local curvature radius, which decreases in the infrared. In addition, the bounce action is not enhanced by large numbers. These features allow the transition to successfully complete over a wider parameter range than for Goldberger-Wise stabilized RS models. Due to the increase of L(y) in the ultraviolet, the throat has a reliable gravitational description even when the number of infrared degrees of freedom is small. We also comment on aspects of the thermal phase transition in Higgsless models, where the gauge symmetry breaking is achieved via boundary conditions. Such models include orbifold-GUT models and the Higgsless electroweak symmetry breaking theories of Csaki et al, with Standard Model gauge fields living in the bulk.