Speaker
Description
XENONnT is a dual-phase liquid xenon time projection chamber operating at LNGS with a 5.9-tonne active target, designed to search for weakly interacting massive particles (WIMPs). As its sensitivity reaches the irreducible background from solar neutrino coherent scattering, the experiment enters a new regime — the "neutrino fog" — where neutrino and dark matter signals become increasingly difficult to disentangle.
We report a 3.3σ measurement of coherent elastic neutrino-nucleus scattering (CEνNS) from solar $^8$B neutrinos using a combined exposure of 6.77 t×yr across three science runs. The inferred $^8$B flux of ($5_{-2}^{+3}$) $\times 10^6 \mathrm{cm^{-2}s^{-1}}$ is consistent with the Standard Solar Model. In the presence of this neutrino fog, a search for light dark matter finds no signal excess, and a near-doubling of exposure improves the median sensitivity to 5 GeV/c² WIMPs by only ~10%, providing a direct experimental demonstration of diminishing returns.
The dataset is further used to measure the weak mixing angle $sin^2 θ_W$ at ~0.02 GeV/c momentum transfer and to constrain new vector mediators and the neutrino magnetic moment, highlighting the versatility of the liquid xenon TPC as a precision probe of both neutrino physics and physics beyond the Standard Model.
| 请选择分会 | 中微子物理、粒子天体物理与宇宙学 |
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