The LUX-ZEPLIN (LZ) experiment has reported an anomalous single candidate event in the high-energy nuclear recoil window of $248\pm32.5\ \mathrm{keV}_{\mathrm{nr}}$, with an exposure of $2.80\ \mathrm{ton}\cdot\mathrm{yr}$. This event is notable as the low-energy spectrum measured by LZ remains consistent with background expectations. Researchers propose that this excess could be naturally explained by the neutral-current absorption of fermionic dark matter on xenon nuclei.

Under this hypothesis, a dark matter particle with a mass of $m_\chi \simeq 247\ \mathrm{MeV}$ could produce a monoenergetic nuclear recoil at approximately $248\ \mathrm{keV}_{\mathrm{nr}}$ through coherent absorption. At this momentum transfer, the absorption process would enter an incoherent regime, where scattering off individual nucleons produces a broad recoil spectrum extending from about $200\ \mathrm{keV}$ to $100.2\ \mathrm{MeV}$. A single effective field theory (EFT) coupling could simultaneously produce this one event in the specified window while remaining consistent with the non-observation of events in neighboring energy regions.

The required single-nucleon absorption cross section for this scenario is $ \sigma_{\chi N}^{\mathrm{NC}} = 1.07\times10^{-46}\ \mathrm{cm}^2$, corresponding to an effective field theory scale of $ \Lambda \simeq 11.5\ \mathrm{TeV}$. However, a recasting analysis of KamLAND data on the neutron-emission channel $ \chi+{}^{12}\mathrm{C} \to \nu+ n + {}^{11}\mathrm{C}^*$ excludes this benchmark parameter space. This establishes a significant tension between the LZ excess interpretation and existing constraints from large-volume scintillator detectors, highlighting the need for future dedicated high-energy analyses to resolve this discrepancy.