Transient pulses from exploding primordial black holes as a signature of an extra dimension

An evaporating black hole in the presence of an extra spatial dimension would undergo an explosive phase of evaporation. We show that such an event, involving a primordial black hole, can produce a detectable, distinguishable electromagnetic pulse, signaling the existence of an extra dimension of size L ∼ 10⁻¹⁸ − 10⁻²⁰ m. We derive a generic relationship between the Lorentz factor of a pulse-producing “fireball” and the TeV energy scale. For an ordinary toroidally compactified extra dimension, transient radio-pulse searches probe the electroweak energy scale (∼0.1 TeV), enabling comparison with the Large Hadron Collider.