Speaker
Description
We study the sensitivity of liquid xenon detectors to monochromatic 5.5 MeV solar axions from pp chain in the Sun, for axion masses from 0 to 1 MeV. For the axion-electron coupling, three channels are considered: axion-induced pair production, inverse Compton scattering, and the axio-electric effect; for the axion-photon coupling, we consider the inverse Primakoff process. We compute for the first time the effect of a finite axion mass on the pair production cross section, finding a universal mass enhancement of R ~ 100 as $m_a \to 1$MeV. The high atomic number of xenon (Z = 54) further enhances the pair production cross section by a factor of ~ 80 relative to carbon-based detectors. Benefiting from these two enhancements, the future PandaX-xT (200 ton-yr) is projected to reach ~ $1.3 \times 10^-13$, and XLZD (1000 ton-yr) ~ $5.9 \times 10^-14$, both surpassing the Borexino limit and comparable to the projected sensitivities of JUNO and Hyper-Kamiokande despite their much larger exposures. For the axion photon coupling, PandaX-XT and XLZD also surpass the current Borexino limit. These results demonstrate that liquid xenon detectors provide a competitive and complementary platform for probing MeV-scale solar axions.