Does the measured solar 8B CEvNS rate in xenon match the Standard Model?
In plain words
Xenon dark matter detectors have begun to see solar neutrinos gently bumping whole xenon nuclei, a process called coherent scattering. The question is whether the measured rate equals the Standard Model prediction or hints at new neutrino interactions.
Precise statement
Coherent elastic neutrino-nucleus scattering (CEvNS) of solar 8B neutrinos on Xe produces nuclear recoils below a few keV. The quantity is the measured 8B flux (or CEvNS rate) inferred from xenon data, compared with the SM cross section and the solar-model and SNO flux of about $5.2e6\ \mathrm{cm}^{-2}\ \mathrm{s}^{-1}$. An answer is a measurement with 10 percent precision and the resulting bound on nonstandard neutrino-quark couplings or light mediators.
What would settle it
A xenon (or argon) detector measurement of the 8B CEvNS rate with low enough threshold and calibrated nuclear-recoil response to reach about 10 percent uncertainty.
Status in the literature
Unverified note
XENONnT ($2.73\sigma$) and PandaX-4T ($2.64\sigma$) reported evidence in 2024 (Phys. Rev. Lett. 133, 191002 and 191001); in 2026 LZ reported $4.5\sigma$ (Phys. Rev. Lett. 137, 091806) and XENONnT $3.3\sigma$ with flux $(5 +3 -2)e6\ \mathrm{cm}^{-2}\ \mathrm{s}^{-1}$ (Phys. Rev. Lett. 137, 091807); flux uncertainties remain about 50 percent.