Constraining Axion-Like-Particles with germanium detector at the Kuo-Sheng Reactor Neutrino Laboratory

Abstract

We present results of a search for Axion-Like Particles (ALPs) produced $via$ Primakoff and Compton-like scattering channels, using data acquired with TEXONO experiment at the Kuo-Sheng Nuclear Power Station. The analysis is based on 278.91 days of reactor-ON and 43.60 days of reactor-OFF data. These datasets were collected using a 1.06 kg high-purity germanium detector located 28 m from a 2.9 GW reactor core. No significant excess is observed in the residual spectrum from the reactor-ON and reactor-OFF data subtraction. Using data acquired with low-background germanium detectors, upper limits on both the ALP-photon ($g_{aγγ}$) and ALP-electron ($g_{aee}$) couplings are derived for ALP masses ranging from 1 eV to 3 MeV at 90\% confidence level. Since both $g_{aγγ}$ and $g_{aee}$ couplings contribute to ALP production and detection, a combined analysis is performed by treating both channels as active parameters.