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Title: Do GeV-scale heavy neutral leptons realize low-scale leptogenesis?
Plain: In one scenario, heavy partners of neutrinos with masses near a few proton masses created the asymmetry. Such particles could be made at accelerators and seen decaying.
Precise: Determine whether heavy neutral leptons N with $M_N \sim 0.1\ \text{to}\ 100\ \mathrm{GeV}$ and active-sterile mixing $U^2$ in the range where resonant or oscillation-based (ARS) leptogenesis gives $\eta_B \sim 6e-10$ exist. An answer is a discovery with measured $M_N$, $U_e^2$, $U_{\mu}^2$, $U_{\tau}^2$ consistent with that region, or its exclusion.
Settled by: Beam-dump and collider searches (SHiP, displaced-vertex searches at LHC, FCC-ee at the Z pole) covering the leptogenesis region.
Kind: well-posed
Answer type: yes-no
References: (empty)
Literature status: open
Status note: SHiP was approved at CERN in 2024 for operation in the 2030s.
Posed since: 1998