Probing axion-like particles at the Electron-Ion Collider

Abstract

The Electron-Ion Collider~(EIC), a forthcoming powerful high-luminosity facility, represents an exciting opportunity to explore new physics. In this article, we study the potential of the EIC to probe the coupling between axion-like particles~(ALPs) and photons in coherent scattering. The ALPs can be produced via photon fusion and decay back to two photons inside the EIC detector. In a prompt-decay search, we find that the EIC can set the most stringent bound for $m_a\lesssim 20\text{GeV}$ and probe the effective scales $\Lambda \lesssim 10^5$GeV. In a displaced-vertex search, which requires adopting an EM calorimeter technology that provides directionality, the EIC could probe ALPs with $m_a\lesssim 1\text{GeV}$ at effective scales $\Lambda \lesssim 10^7\text{GeV}$. Combining the two search strategies, the EIC can probe a significant portion of unexplored parameter space in the $0.2<m_a<20\text{GeV}$ mass range.

Comments: 23 pages, 9 figures