Solitons in the supersymmetric extensions of the Standard Model

TL;DR

The paper demonstrates that supersymmetric extensions of the Standard Model generically admit stable non-topological solitons of the Q-ball type carrying baryon number $B$, lepton number $L$, and electric charge. It develops a multi-field framework for Q-balls, analyzes the large-$Q$ thin-wall regime, and introduces thick-wall Q-beads for small $Q$, with quantitative conditions and scaling relations for their mass and size. It then specializes to the MSSM, showing how $B$-, $L$-, and electric-charge-carrying Q-balls arise from cubic Yukawa couplings and soft terms, including toy models that ensure the existence of stable lepton- or baryon-bead solitons. The cosmological implications are emphasized: production in the early Universe, nonstandard nucleosynthesis, potential dark matter roles for Q-beads, and possible leptoquark-like interactions, which together broaden the phenomenology and constrain MSSM parameters.

Abstract

All supersymmetric generalizations of the Standard Model allow for stable non-topological solitons of the Q-ball type which may have non-zero baryon and lepton numbers, as well as the electric charge. These solitons can be produced in the early Universe, can affect the nucleosynthesis, and can lead to a variety of other cosmological consequences.