CosmoCoffee Forum Index CosmoCoffee

 
 FAQFAQ   SearchSearch  MemberlistSmartFeed   MemberlistMemberlist    RegisterRegister 
   ProfileProfile   Log inLog in 
Arxiv New Filter | Bookmarks & clubs | Arxiv ref/author:

[0706.3388] A Confining Strong First-Order Electroweak Phase Transition
 
Authors:Germano Nardini, Mariano Quiros, Andrea Wulzer
Abstract:In the Randall-Sundrum model where the radion is stabilized by a Goldberger-Wise (GW) potential there is a supercooled transition from a deconfined to a confined phase at temperatures orders of magnitude below the typical Standard Model critical temperature. When the Higgs is localized at the IR brane the electroweak phase transition is delayed and becomes a strong first-order one where the Universe expands by a few e-folds. This generates the possibility of having the out-of-equilibrium condition required by electroweak baryogenesis in the electroweak phase transition. We have studied numerically the region of the GW parameter space where the theory is consistent and the latter possibility is realized. We have found that in most of the parameter space the nucleation temperature is so low that sphalerons are totally inactive inside the bubbles. The condition for sphalerons to be inactive after reheating imposes an upper bound on the reheating temperature that is weaker for heavy Higgs bosons so that the out-of-equilibrium condition seems to favor heavy over light Higgses. The condition for sphalerons to be active outside the bubbles puts an upper bound on the number of e-folds at the phase transition, roughly consistent with the critical value required by low-scale inflation to solve the cosmological horizon problem.
[PDF] [PS] [BibTex] [Bookmark]

Post new topic   Reply to topic    CosmoCoffee Forum Index -> arXiv papers
View previous topic :: View next topic  
Author Message
Thomas Dent



Joined: 14 Nov 2006
Posts: 28
Affiliation: ITP Heidelberg

PostPosted: June 25 2007  Reply with quote

This is a suggestion of how to get a non-standard and strongly first order electroweak phase transition in a particular class of extra-dimensional theory:

Quote:
In the Randall-Sundrum model where the radion is stabilized by a Goldberger-Wise (GW) potential there is a supercooled transition from a deconfined to a confined phase at temperatures orders of magnitude below the typical Standard Model critical temperature.
When the Higgs is localized at the IR brane the electroweak phase transition is delayed and becomes a strong first-order one where the Universe expands by a few e-folds.


The Randall-Sundrum model already has a phase transition which may be seen in 'dual' gauge theory as a deconfinement-confinement transition, or in 5d gravity as the emergence of the IR brane versus the high temperature state of a black hole in AdS space. Then the authors study the behaviour on a more realistic theory with stabilized radion and Higgs. It appears that the electroweak phase transition happens much later and much cooler than in standard 4d cosmology.

One possible spanner in the works is described in
0706.1111

which I noticed a couple of weeks ago. That paper is the latest of many that look at the density in primordial black holes (4d black holes, of course, not 5d!) produced at cosmological phase transitions. One result is that the PBH's forming at strong first-order transitions overclose the Universe by an enormous factor under quite general assumptions.

However, that is a purely 4d analysis and one might have to think more carefully what could happen in a 5d model.

If RS models all have a strongly first-order phase transition then the question of PBH formation becomes rather urgent ... has anyone thought about it?
Back to top
View user's profile   Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    CosmoCoffee Forum Index -> arXiv papers All times are GMT + 5 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group. Sponsored by WordWeb online dictionary and dictionary software.