Accelerating strangelets via Penrose process in non-BPS fuzz-balls

We discuss how the Penrose process, taking place in singular rotating Kerr black holes as well as in their smooth, horizonless fuzz-ball counterparts in string theory, may provide an efficient mechanism for the acceleration of Ultra High Energy Cosmic Rays, including strangelets, a form of Strange Quark Matter that is under active experimental investigation with Mini-EUSO. We focus on non-BPS solutions of the JMaRT kind that present an ergo-region. We study geodetic motion and the (non-collisional) Penrose process in this context. In particular we compute its efficiency that turns out not to be bounded unlike for Kerr BH's and briefly comment on possible implications for near-future observations. (C) 2020 The Authors. Published by Elsevier B.V.