Measuring heavy neutrino couplings at the LHC

The existence of heavy neutrinos mediating neutrino masses via a type-I seesaw can be directly probed at the LHC, or indirectly in rare lepton flavor-violating processes. The synergy between these two approaches requires a direct measurement of the heavy neutrino couplings. We discuss a strategy to perform such measurements at the LHC in the context of left-right symmetric models, which is also applicable to other models implementing a type-I or type-III seesaw. We demonstrate that the ambiguities in the determination of the heavy neutrino mixing parameters can be resolved by performing an exclusive analysis of dilepton final states, discriminated by flavor and missing energy.This work has been supported by the and Fundação para a Ciência e a Tecnologia (FCT, Portugal) and Ministerio de Ciencia e Innovación (MICINN, Spain) under the bilateral project “Signals of new fermions at colliders” (FCT/1683/27/1/2012/S, AIC-D-2011-0811). J.A.A.S. acknowledges support from the projects FPA2006-05294, FPA2010-17915 and the Junta de Andalucía projects FQM 101, FQM 03048 and FQM 6552. F.R.J. thanks the CERN Theory Division for hospitality during the final stage of this work and acknowledges support from the EU Network grant UNILHC PITN-GA-2009-237920 and from the FCT projects CERN/FP/123580/2011, PTDC/FIS/098188/2008 and CFTP-FCT UNIT 777