Displaced fat-jets and tracks to probe boosted right-handed neutrinos in the $$U(1)_{B-L}$$ model

Abstract

AbstractWe investigate the pair-production of Right-Handed Neutrinos (RHNs) via a $$B-L$$ B - L $$Z'$$ Z ′ boson and present the sensitivity studies of the active-sterile neutrino mixing ($$|V_{\mu N}|$$ | V μ N | ) at the High-Luminosity run of the LHC (HL-LHC) and a future pp collider (FCC-hh). We focus on RHN states with a mass of $$10-70$$ 10 - 70  GeV which naturally results in displaced vertices for small $$|V_{\mu N}|$$ | V μ N | . Being produced through a mass resonance with $$M_{Z'} \ge 1$$ M Z ′ ≥ 1  TeV, the RHNs are heavily boosted, leading to collimated decay products that give rise to fat-jets. We investigate the detection prospect of dedicated signatures in the inner detector and the muon spectrometer, namely a pair of displaced fat-jets and the associated tracks, respectively. We find that both the HL-LHC and FCC-hh can be sensitive to $$|V_{\mu N}| > 10^{-6}$$ | V μ N | > 10 - 6 and $$|V_{\mu N}| > 10^{-7}$$ | V μ N | > 10 - 7 with the number of events reaching $${\mathcal {O}}(10)$$ O ( 10 ) and $${\mathcal {O}}(10^3)$$ O ( 10 3 ) , respectively. This allows probing the generation of light neutrino masses through the Seesaw mechanism.