TY  - JOUR
AU  - Dorsch, Gláuber C.
AU  - Konstandin, Thomas
AU  - Perboni, Enrico
AU  - Pinto, Daniel A.
TI  - Non-singular solutions to the Boltzmann equation with a fluid Ansatz
JO  - Journal of cosmology and astroparticle physics
VL  - 04
IS  - 04
SN  - 1475-7508
CY  - London
PB  - IOP
M1  - PUBDB-2025-05795
M1  - arXiv:2412.09266
M1  - DESY-24-193
SP  - 033 -
PY  - 2025
N1  - 33 pages, 20 figures
AB  - Cosmological phase transitionscan give rise to intriguing phenomena, such as baryogenesis or a stochastic gravitational wave background, due to nucleation and percolation of vacuum bubbles in the primordial plasma. A key parameter for predicting these relics is the bubble wall velocity, whose computation relies onsolving the Boltzmann equations of the various speciesalong the bubble profile. Recently it has been shown that an unphysical singularity emerges if one assumes these local quantities to be described as small fluctuations on a constant equilibrium background.In this work we solve this issue by including the spatial dependence of thebackground into the fluid Ansatz. This leads to a modification of the Boltzmann equation, and all terms that would give rise to a singularity now vanish.We recalculate the different contributions to the counter-pressure of the plasma on the expanding wall, and discuss their relative importance. The Standard Model with a low cutoff is chosen as benchmark model and the results are shown for different values of the cutoff scale Λ. In this setup, deflagration solutions are found for almost all the values of Λ considered, while detonations are found only for some restricted corner of the parameter space.
KW  - cosmological phase transitions (autogen)
KW  - particle physics - cosmology connection (autogen)
KW  - physics of the early universe (autogen)
KW  - primordial gravitational waves (theory) (autogen)
LB  - PUB:(DE-HGF)16
DO  - DOI:10.1088/1475-7516/2025/04/033
UR  - https://bib-pubdb1.desy.de/record/643046
ER  -