The LZ inelastic splitting as a probe of anomaly mediation

Abstract

The LZ 248 keV recoil candidate admits an interpretation in terms of pseudo-Dirac dark matter with a mixing-suppressed inelastic $Z$ interaction. In the MSSM, the Higgsino limit conflicts with the adopted solar-neutrino bound, while a gaugino realization requires an unprotected mass degeneracy. We realize such spectra in the MRSSM, where an $R$-symmetric Dirac bino produces the required $Z$ transition and wino coannihilation supplies the observed relic abundance. We impose the Higgs and gauge coupling relations of $N=2$ supersymmetry at a high scale and evolve them to low energy. With the remaining model parameters held fixed, we obtain spectra spanning roughly 300-850 GeV that satisfy the adopted constraints and have a small diagonal axial current. If anomaly mediation dominates the Majorana splitting, its local scale is tens of MeV for splittings of a few hundred keV. A five-dimensional warped construction generates this scale through Goldberger-Wise stabilization and a loop correction to the no-scale Kähler potential. The spectra remain testable through elastic scattering, solar neutrinos and long-lived charged states.