Researchers have developed a theory proposing a new type of dark matter, a dark baryon, that could explain an anomalous event observed in the LZ (LUX-ZEPLIN) experiment. This model posits that dark matter interacts with atomic nuclei predominantly through inelastic scattering mediated by a transition magnetic dipole operator. Elastic scattering is suppressed due to accidental symmetries within the strongly-coupled sector of the model, distinguishing it from other inelastic dark matter proposals.

The model suggests that the nuclear response is dominated by a spin-dependent structure factor. This allows a wide range of dark matter particle masses, between 1 TeV and 50 TeV, and an inelastic mass splitting (δ) between 100 keV and 500 keV, to be consistent with the LZ experiment data, even considering various dark matter velocity distributions. This mass splitting is crucial for the inelastic nature of the interaction.

A distinctive prediction of this theory is that some nuclear scattering events would be accompanied by a simultaneous photon signal with an energy equal to the mass splitting δ. This feature would not only help distinguish this model from other inelastic dark matter explanations but could also enable directional detection in conventional direct detection experiments. The authors also briefly comment on dark matter abundance, indirect detection signals (including significantly weaker constraints from dark matter annihilation in the Sun), and associated collider signals arising from the mesonic sector of the theory.