Determining the lifetime of long-lived particles at the HL-LHC Shankha Banerjee, Biplob Bhattacherjee, Andreas Goudelis, Björn Herrmann, Dipan Sengupta and Rhitaja Sengupta Eur. Phys. J. C, 81 2 (2021) 172 Published online: 19 February 2021 DOI: 10.1140/epjc/s10052-021-08945-9