Heavy neutrinos at the FCC-hh in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>U</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mn>1</mml:mn><mml:msub><mml:mo stretchy="false">)</mml:mo><mml:mrow><mml:mi>B</mml:mi><mml:mo>?</mml:mo><mml:mi>L</mml:mi></mml:mrow></mml:msub></mml:math> model

We investigate the potential of 100 TeV future circular collider (FCC-hh) to probe heavy neutrinos. concentrate in particular on neutrino production via a $U(1{)}_{B\ensuremath{-}L}$ ${Z}^{\ensuremath{'}}$ gauge boson and contrast resulting limits with that mediated by Standard Model weak currents. consider decays semileptonic as well fully leptonic final states, particularly muon flavor, we show importance considering searches both prompt displaced For modes are more promising due smaller background larger yields, TeV-scale neutrinos active-sterile mixing compatible light mass generation seesaw scenario can be probed for 5 coupling low ${g}_{B\ensuremath{-}L}={10}^{\ensuremath{-}2}$. Displaced vertex extend this range masses 10 GeV.