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Description
This work explores the production of MeV-scale electrophilic axion-like particles (ALPs) by utilizing the monochromatic 5.5 MeV photon resulting from the nuclear fusion processes in the Sun. These 5.5 MeV photons can undergo Compton-like scattering with the ambient electrons in the solar matter to produce a substantial flux of MeV ALPs. Upon reaching the Earth, such ALPs can be detected via the same electron coupling, offering a new opportunity for the dark matter (DM) direct detection experiments to probe the previously unexplored parameter regions. We show that the existing data of LZ, PandaX-4T, and Borexino can attain the sensitivities gae ≲ 3.7 × 10−6 , gae ≲ 3.7 × 10−6 and gae ≲ 1.7 × 10−6 , respectively, for ma ≲ 1 MeV. An optimistic 200 tonne×year exposure by PandaX-xT can reach gae ≲ 1.6 × 10−6 for most of the mass window ma < 1,MeV and even gae ≲ 1.5 × 10−7 with ma approaching 1 MeV. Despite the stringent constraints from different laboratory experiments and astrophysical observations, our obtained limits from LZ, PandaX-4T, and Borexino can probe new parameter regions, specifically in the mass window 0.4 MeV ≲ ma ≲ 1 MeV.