Year: 2024
Type: article
Abstract: A bstract Collider-testable type I seesaw extensions of the Standard Model are generally protected by an approximate lepton number (LN) symmetry. Consequently, they predict pseudo-Dirac heavy neutral leptons (HNLs) composed of two nearly degenerate Majorana fields. The interference between the two mass eigenstates can induce heavy neutrino-antineutrino oscillations ( $$ N\overline{N}\textrm{Os} $$ N N ¯ Os ) leading to observable lepton number violation (LNV), even though the LN symmetry is approximately conserved. These $$ N\overline{N}\textrm{Os} $$ N N ¯ Os could be resolved in long-lived HNL searches at collider experiments, such as the proposed Future Circular e + e − Collider (FCC- ee ) or Circular Electron Positron Collider (CEPC). However, during their Z -pole runs, the LN carried away by the light (anti)neutrinos produced alongside the HNLs prevents LNV from being observed directly. Nevertheless, $$ N\overline{N}\textrm{Os} $$ N N ¯ Os materialise as oscillating signatures in final state distributions. We discuss and compare a selection of such oscillating observables, and perform a Monte Carlo simulation to assess the parameter space in which $$ N\overline{N}\textrm{Os} $$ N N ¯ Os could be resolved.
Source: Journal of High Energy Physics
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4404614270