Timescale for trans-Planckian collisions in Kerr spacetime Mandar Patil, Pankaj S. Joshi, Ken-ichi Nakao, Masashi Kimura and Tomohiro Harada EPL, 110 3 (2015) 30004 Published online: 21 May 2015 DOI: 10.1209/0295-5075/110/30004