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Title: Reflections on bubble walls
A<sc>bstract</sc> We discuss the dynamics of expanding bubble walls in the presence of massive dark photons whose mass changes as they cross the wall. For sufficiently thin walls, we show that there exists a transient kinematic regime characterized by a constant reflection probability of longitudinal — but not transverse — modes. This effect can have important implications for the dynamics of expanding vacuum bubbles in the early Universe. Most notably, it leads to a new source of pressure on the expanding interface, featuring a non-monotonic dependence on theγ-factor of the bubble walls and reaching a peak at intermediateγ-factors that we dub Maximum Dynamic Pressure. When this pressure is large enough to halt the acceleration of the bubble walls, the difference in vacuum energy densities goes into making a fraction of the dark photons relativistic, turning them into dark radiation. If the dark radiation remains relativistic until late times, an observable contribution to ∆Neffis possible for phase transitions with strengthα∼ 10−2−10−1.  more » « less
Award ID(s):
2207584
PAR ID:
10499748
Author(s) / Creator(s):
; ;
Publisher / Repository:
https://inspirehep.net/
Date Published:
Journal Name:
Journal of High Energy Physics
Volume:
2023
Issue:
9
ISSN:
1029-8479
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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