Heavy Majorana neutrino pair productions at the LHC in minimal U(1) extended Standard Model Arindam Das, Nobuchika Okada and Digesh Raut Eur. Phys. J. C, 78 9 (2018) 696 Published online: 31 August 2018 DOI: 10.1140/epjc/s10052-018-6171-8