Particle creation from Q-balls

Abstract

Non topological solitons, Q-balls can arise in many particle theories with U (1) global symmetries.As was shown by Cohen et al. [2], if the corresponding scalar field couples to massless fermions, large Q-balls are unstable and evaporate, producing a fermion flux proportional to the Q-ball's surface. In this paper we analyse Q-ball instabilities as a function of Q-ball size ans fermion mass.In particular, we construct an exact quantum-mechanical description of the evaporating Q-ball.This new construction provides an alternative method to compute Q-Ball's evaporation rates. We shall also find the new expression for the upper bound on evaporation as a function of the produced fermion mass and study the effects of Q ball's size on particle production.

Astrophysical constraints on dark-matter Q -balls in the presence of baryon-violating operators

“…Much work has been done calculating the decay and evaporation rates and energy spectra of Q-ball decays to fermions (both massless and massive) [22,23]. However, these previous studies did not treat decay of the condensate to bosons, and are related, but not relevant to the problem at hand.…”

Recrudescence of massive fermion production by oscillons

“…If we view them as small lumps of preheating-phase physics, we might expect them to be able to emit heavy fermions rather efficiently, just as homogeneous preheating does. In this initial study we shall ignore the effects of back-reaction from the fermions onto the oscillon, and use techniques introduced by Cohen, Coleman, Georgi and Manohar [37], and followed up by [38][39][40]. In these the authors examined fermion emission from Q-balls [41], and calculated the particle production using a Bogoliubov-type analysis.…”

Compact Q-balls in the complex signum-Gordon model

“…3. In general, Q-ball dynamics is very complex already on the level of purely classical theory, see, e.g., [5], and still richer when one includes quantum effects, see, e.g., [14] and references therein. The simplicity of the Q-balls of the complex signum-Gordon model can perhaps facilitate the theoretical studies, and make them interesting for applications.…”