# Particle Creation from Non-topological Solitons

Abstract : Non topological solitons, Q balls can arise in many particle theories with $U(1)$ global symmetries. As was shown by
Cohen et al. [A.G. Cohen, S.R. Coleman, H. Georgi and A. Manohar,
Nucl.Phys.B272 (1986) 301.], 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 work we analyse Q-ball instabilities as a
function of Q-ball size and 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 a new expression for
the upper bound on evaporation as a function of the produced fermion mass and study the effects of the size of the Q ball on particle production.

We also analyse what happens if external fermion is scattered on a Q ball and
demonstrate that it can be converted into antiparticle with a probability of
the order of one. This result has important implications for astrophysical
applications of dark matter Q balls.
Mots-clés :
Document type :
Theses

Cited literature [24 references]

https://tel.archives-ouvertes.fr/tel-00087796
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Submitted on : Friday, July 28, 2006 - 4:27:22 PM
Last modification on : Monday, October 2, 2017 - 4:06:02 PM
Long-term archiving on: : Monday, April 5, 2010 - 10:26:06 PM

### Identifiers

• HAL Id : tel-00087796, version 1

### Citation

Stephen Clark. Particle Creation from Non-topological Solitons. High Energy Physics - Experiment [hep-ex]. Ecole Polytechnique Fédérale de Lausanne (EPFL), 2006. English. ⟨tel-00087796⟩

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