Detecting Axion-like Particles with Plasmon in Reactor-based Experiment

Abstract: Axion and axion-like particles (ALPs), predicted by various extensions of the Standard Model, can be copiously produced in nuclear reactors via the Primakoff process. In this work, we explore the detection of such relativistic ALPs through the plasmon effect in silicon detectors located near reactors. Utilizing the data from the Connie and Atucha-II experiments, we set the 90\% confidence level upper limits on the ALP-photon coupling $g_{aγ}$ over the mass range $0.1< m_a <100$ keV. Furthermore, we present that the projected sensitivity of the Oscura experiment, with an exposure of 30 kg$\cdot$ yr, will surpass the current reach of the NEON experiment by approximately one order of magnitude in the same mass range. This improvement would substantially expand the explored region of the QCD axion and ALP parameter space.