Hunting for sterile neutrino with future collider signatures

TL;DR

This paper assesses the potential to detect sterile neutrinos at future colliders through various production and decay channels, providing new experimental constraints and exploring multiple signatures across collider types.

Contribution

It introduces novel detection channels and methods for sterile neutrinos at colliders, including $e^+e^-$, $ep$ collisions, heavy hadron decays, and Higgs decays, with improved sensitivity estimates.

Findings

Enhanced sensitivity for light sterile neutrinos at SuperKEKB, CEPC, and ILC.

Proposed new production channel via proton bremsstrahlung in $ep$ collisions.

Derived new limits on active-sterile mixing angles in GeV mass range.

Abstract

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 $e^+e^-\to\bar{\nu}_e N$ channel is explored with new signal selection method which tends to be efficient for light $m_N$, the constraints of active-sterile mixing $|U_{eN}|^2$ 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 proton bremsstrahlung, i.e., $e^-\gamma \to NW^-$, 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 $\Lambda_c,\ \Xi_{c},\ \Xi_{cc}$ and $\Lambda_b$ are explored via an intermediate on-shell Majorana neutrino in GeV scale. The branching fractions and the constraints for $|U_{\ell N}|^2$ are given, and hence may put new limits on this mass region. The ${\rm Higgs} \to W\mu\mu\pi$ channel is also considered to test massive neutrino within Higgs sector.