GUT-induced FCC signatures of the LUX-ZEPLIN event

Abstract

The recent observation of an event with large recoil energy at LUX-ZEPLIN has found a possible explanation in terms of the inelastic scattering of a pseudo-Dirac particle like the Higgsino of the MSSM. For pseudo-Dirac dark matter, the mass splitting $δm$ is correlated with the mass of some heavier states. While rough dimensional considerations seem to indicate mass ranges of the heavy particles hopelessly out of reach even at future colliders, we point out that this is not the case in GUT-induced scenarios. Working with a specific model based on SU(6), we show that the experimentally favored $δm$ implies the presence of a $Z'$ gauge boson with a mass in the 10s of TeV. We derive the predicted $Z'$ signal in the dilepton channel and we confront it with the sensitivity of the FCC-$hh$ to $Z'$ resonances. We show that the $Z'$ falls squarely in reach of the early discovery potential of the FCC-$hh$.