Hunting for sterile neutrino with future collider signatures

We study the feasibility to observe sterile neutrino at the high energy colliders with direct production channels through e+e−, ep collision, and indirect production channels through decays of heavy meson, baryon and Higgs. For e+e− collision, the e+e−→ν¯eN channel is explored with new signal selection method which tends to be efficient for light mN, the constraints of active-sterile mixing |UeN|2 at the SuperKEKB, CEPC and ILC are expected to reach better lower limits than current experiments. For ep collision, We investigate the heavy sterile neutrino production through a new channel via photon PDF, i.e., e−γ→NW−, hundreds of GeV heavy sterile neutrino can be probe and new limit on mixing is given. For heavy hadrons decay, the lepton-number-violating decays of Λc,Ξc,Ξcc and Λb are explored via an intermediate on-shell Majorana neutrino in GeV scale. The branching fractions and the constraints for |UℓN|2 are given, and hence may put new limits on this mass region. The Higgs→Wμμπ channel is also considered to test massive neutrino within Higgs sector.