分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: Dual-phase xenon time projection chamber (TPC) detectors have demonstrated superior search sensitivities to dark matter over a wide range of particle masses. To extend their sensitivity to include low-mass dark matter interactions, it is critical to characterize both the light and charge responses of liquid xenon to sub-keV nuclear recoils. In this work, we report a new nuclear recoil calibration in the LUX detector $\textit{in situ}$ using neutron events from a pulsed Adelphi Deuterium-Deuterium neutron generator. We demonstrate direct measurements of light and charge yields down to 0.45 keV (1.4 scintillation photons) and 0.27 keV (1.3 ionization electrons), respectively, approaching the physical limit of liquid xenon detectors. We discuss the implication of these new measurements on the physics reach of dual-phase xenon TPCs for nuclear-recoil-based low-mass dark matter detection.
分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: We present the results from combining machine learning with the profile likelihood fit procedure, using data from the Large Underground Xenon (LUX) dark matter experiment. This approach demonstrates reduction in computation time by a factor of 30 when compared with the previous approach, without loss of performance on real data. We establish its flexibility to capture non-linear correlations between variables (such as smearing in light and charge signals due to position variation) by achieving equal performance using pulse areas with and without position-corrections applied. Its efficiency and scalability furthermore enables searching for dark matter using additional variables without significant computational burden. We demonstrate this by including a light signal pulse shape variable alongside more traditional inputs such as light and charge signal strengths. This technique can be exploited by future dark matter experiments to make use of additional information, reduce computational resources needed for signal searches and simulations, and make inclusion of physical nuisance parameters in fits tractable.