1. Exclusion of the Cosmological Triangle in Reactor-Based Search for Axion-Like Particles
- Author
-
Park, Byung Ju, Choi, Jae Jin, Jeon, Eunju, Kim, Jinyu, Kim, Kyungwon, Kim, Sung Hyun, Kim, Sun Kee, Kim, Yeongduk, Ko, Young Ju, Koh, Byoung-Cheol, Ha, Chang Hyon, Lee, Seo Hyun, Lee, In Soo, Lee, Hyunseok, Lee, Hyun Su, Lee, Jaison, Oh, Yoomin, and Kim, Doojin
- Subjects
High Energy Physics - Experiment - Abstract
We report new constraints on axion-like particle (ALP) using data corresponding to a sodium iodine target exposure of 3063 kg$\cdot$days from the neutrino elastic scattering observation with NaI (NEON) experiment. A 16.7 kg of thallium-doped sodium iodide target was located 23.7 meters from a 2.8 GW thermal power nuclear reactor. We searched for ALPs produced by high-flux photons by comparing the energy spectra of data collected during reactor-on (1596 kg$\cdot$days exposure) and reactor-off (1467 kg$\cdot$days exposure) periods. No signal consistent with ALP interaction was identified, allowing us to set exclusion limits at the 95% confidence level. Our limits cover previously unexplored regions for both photon couplings (${g_{a\gamma}}$) and electron couplings (${g_{ae}}$) for axion masses around 1 MeV/c$^2$. Notably, the NEON data excludes the unconstrained region identified by laboratory-based searches for photon couplings within the "cosmological triangle" for the first time. The observed 95\% confidence level limits reach as low as ${g_{a\gamma}}$ of 4.33$\times$ 10$^{-8}$ GeV$^{-1}$ and ${g_{ae}}$ of 1.10$\times$ 10$^{-9}$ for axion masses of 1.7 MeV/c$^2$ and 1.0 MeV/c$^2$, respectively.
- Published
- 2024