We study particle production at the collision of two domain walls in 5-dimensional Minkowski spacetime. This may provide the reheating mechanism of an ekpyrotic (or cyclic) brane universe, in which two BPS branes collide and evolve into a hot big bang universe. We evaluate a production rate of particles confined to the domain wall. The energy density of created particles is given as ρ ≈ 20g-4 Nbmn4 where g is a coupling constant of particles to a domain-wall scalar field, Nb is the number of bounces at the collision and mn is the fundamental mass scale of the domain wall. It does not depend on the width d of the domain wall, although the typical energy scale of created particles is given by ω ∼ 1/d. The reheating temperature is evaluated as TR ≈ 0.88̄Nb1/4. In order to have the baryogenesis at the electro-weak energy scale, the fundamental mass scale is constrained as m n ≥ 1.1 × 107 GeV for ̄ ∼ 10 -5.
|ジャーナル||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|出版ステータス||Published - 2004 12月|
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