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Main Authors: Hamada, Yu, Kawana, Kiyoharu, Kim, TaeHun, Lu, Philip
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2407.11115
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author Hamada, Yu
Kawana, Kiyoharu
Kim, TaeHun
Lu, Philip
author_facet Hamada, Yu
Kawana, Kiyoharu
Kim, TaeHun
Lu, Philip
contents Q-balls are non-topological solitons in field theories whose stability is typically guaranteed by the existence of a global conserved charge. A classic realization is the Friedberg-Lee-Sirlin (FLS) Q-ball in a two-scalar system where a real scalar $χ$ triggers symmetry breaking and confines a complex scalar $Φ$ with a global $U(1)$ symmetry. A quartic interaction $κχ^2|Φ|^2$ with $κ>0$ is usually considered to produce a nontrivial Q-ball configuration, and this repulsive force contributes to its stability. On the other hand, the attractive cubic interaction $Λχ|Φ|^2$ is generally allowed in a renormalizable theory and could induce an instability. In this paper, we study the behavior of the Q-ball under the influence of this attractive force which has been overlooked. We find approximate Q-ball solutions in the limit of weak and moderate force couplings using the thin-wall and thick-wall approximations respectively. Our analytical results are consistent with numerical simulations and predict the parameter dependencies of the maximum charge. A crucial difference with the ordinary FLS Q-ball is the existence of the maximum charge beyond which the Q-ball solution is classically unstable. Such a limitation of the charge fundamentally affects Q-ball formation in the early Universe and could plausibly lead to the formation of primordial black holes.
format Preprint
id arxiv_https___arxiv_org_abs_2407_11115
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Q-Balls in the presence of attractive force
Hamada, Yu
Kawana, Kiyoharu
Kim, TaeHun
Lu, Philip
High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
High Energy Physics - Theory
Q-balls are non-topological solitons in field theories whose stability is typically guaranteed by the existence of a global conserved charge. A classic realization is the Friedberg-Lee-Sirlin (FLS) Q-ball in a two-scalar system where a real scalar $χ$ triggers symmetry breaking and confines a complex scalar $Φ$ with a global $U(1)$ symmetry. A quartic interaction $κχ^2|Φ|^2$ with $κ>0$ is usually considered to produce a nontrivial Q-ball configuration, and this repulsive force contributes to its stability. On the other hand, the attractive cubic interaction $Λχ|Φ|^2$ is generally allowed in a renormalizable theory and could induce an instability. In this paper, we study the behavior of the Q-ball under the influence of this attractive force which has been overlooked. We find approximate Q-ball solutions in the limit of weak and moderate force couplings using the thin-wall and thick-wall approximations respectively. Our analytical results are consistent with numerical simulations and predict the parameter dependencies of the maximum charge. A crucial difference with the ordinary FLS Q-ball is the existence of the maximum charge beyond which the Q-ball solution is classically unstable. Such a limitation of the charge fundamentally affects Q-ball formation in the early Universe and could plausibly lead to the formation of primordial black holes.
title Q-Balls in the presence of attractive force
topic High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
High Energy Physics - Theory
url https://arxiv.org/abs/2407.11115