Constraining light sterile neutrino mass with the BICEP2/Keck array 2014 B-mode polarization data Shouvik Roy Choudhury and Sandhya Choubey Eur. Phys. J. C, 79 7 (2019) 557 Published online: 03 July 2019 DOI: 10.1140/epjc/s10052-019-7063-2