Fermion Dark Matter Effect on Electroweak Phase Transition

Fuente: arXiv
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Hauptverfasser: Mirzaie, Soudeh, Ghorbani, Karim, Ghorbani, Parsa
Format: Preprint
Veröffentlicht: 2025
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author Mirzaie, Soudeh
Ghorbani, Karim
Ghorbani, Parsa
author_facet Mirzaie, Soudeh
Ghorbani, Karim
Ghorbani, Parsa
contents The addition of extra scalars to the Standard Model (SM) of particle physics enriches the vacuum structure and consequently gives rise to strong first-order phase transitions (EWPT) in the early universe. We raise the question that how the EWPT is affected by the addition of fermions in models beyond the SM, and address this question by studying the EWPT in a dark matter model comprising a singlet scalar and two Dirac fermions. The singlet scalar develops a nonzero vacuum expectation value (VEV), and the lighter fermion plays the role of the dark matter. The model evades the stringent direct detection bounds due to the presence of two fermions. We first show that applying the high-temperature approximation, no first-order phase transition is found. Then we demonstrate that when including the full finite temperature corrections to the effective potential, the first-order phase transition becomes possible, nevertheless, all the phase transitions will be weak. We therefore deduce that the addition of fermions reduces the strength of the EWPT.
format Preprint
id arxiv_https___arxiv_org_abs_2502_04265
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Fermion Dark Matter Effect on Electroweak Phase Transition
Mirzaie, Soudeh
Ghorbani, Karim
Ghorbani, Parsa
High Energy Physics - Phenomenology
The addition of extra scalars to the Standard Model (SM) of particle physics enriches the vacuum structure and consequently gives rise to strong first-order phase transitions (EWPT) in the early universe. We raise the question that how the EWPT is affected by the addition of fermions in models beyond the SM, and address this question by studying the EWPT in a dark matter model comprising a singlet scalar and two Dirac fermions. The singlet scalar develops a nonzero vacuum expectation value (VEV), and the lighter fermion plays the role of the dark matter. The model evades the stringent direct detection bounds due to the presence of two fermions. We first show that applying the high-temperature approximation, no first-order phase transition is found. Then we demonstrate that when including the full finite temperature corrections to the effective potential, the first-order phase transition becomes possible, nevertheless, all the phase transitions will be weak. We therefore deduce that the addition of fermions reduces the strength of the EWPT.
title Fermion Dark Matter Effect on Electroweak Phase Transition
topic High Energy Physics - Phenomenology
url https://arxiv.org/abs/2502.04265