dE/dx from boosted long-lived particles

At colliders massive long-lived charged particles could be revealed through their anomalously large ionisation energy loss dE/dx. In this paper we explore a class of scenarios in which the LLPs are particularly boosted, owing to production from the decay of a heavy parent resonance. Such scenarios give rise to unique signatures as compared to traditionally considered dE/dx new-physics benchmarks. We demonstrate that this class of models, unlike traditional new-physics theories, can explain the recently reported excess of events in the dE/dx search by the ATLAS collaboration without conflicting with the determination of β from ionisation and time-of-flight measurements.