Searching for axionlike particles at future electron-positron colliders

We investigate the prospects for discovering axionlike particles (ALPs) via a light by light scattering at two colliders, the future circular collider (FCC-ee) and circular electron-positron collider (CEPC). The promising sensitivities to the effective ALP-photon coupling $g_{a\gamma \gamma }$ are obtained. Our numerical results show that the FCC-ee and CEPC might be more sensitive to the ALPs with mass 2–8 GeV than the LHC and CLIC.

Figure 1

The Feynman diagrams of the LBL scattering process induced by the $a\gamma \gamma$ coupling at $e^{+}{e}^{-}$ colliders.

Figure 2

The production cross section $\sigma$ of the LBL scattering process induced by ALPs as a function of the parameter $M_a$ or $g_{a\gamma \gamma }$ at 365 GeV FCC-ee (blue), 240 GeV CEPC (red), and 91 GeV (green).

Figure 3

The typical diagrams for the background of the process $e^{+}{e}^{-}\to \gamma \gamma e^{+}{e}^{-}$.

Figure 4

Normalized distributions of $\eta (e^{\pm })$, $\theta (\gamma \gamma ),\mathrm{\Delta }\theta (e^{+}{e}^{-}),p_T(\gamma \gamma )$ for the signal of selected ALP masses and background at 365 GeV (a, b, c, d, e) and 91 GeV (f, g, h, i, j) FCC-ee with designed luminosities.

Figure 5

The $3\sigma$ and $5\sigma$ curves in the $M_a-g_{a\gamma \gamma }$ plane for $e^{+}{e}^{-}\to \gamma \gamma e^{+}{e}^{-}$ induced by ALP at 365 GeV and 91 GeV FCC-ee with the designed luminosities.

Figure 6

The 95% C.L. exclusion regions on the ALP couplings $g_{a\gamma \gamma }$ as function of $M_a$ from the process $e^{+}{e}^{-}\to \gamma \gamma e^{+}{e}^{-}$ at FCC-ee and other current exclusion regions.

Figure 7

Normalized distributions of $\eta (e^{\pm })$, $\theta (\gamma \gamma )$, $\mathrm{\Delta }\theta (e^{+}{e}^{-})$, $p_T(\gamma \gamma )$ for the signal of selected ALP masses and the background at 240 GeV (a, b, c, d, e) and 91 GeV (f, g, h, i, j) CEPC with the designed luminosities.

Figure 8

The $3\sigma$ and $5\sigma$ curves in the $M_a-g_{a\gamma \gamma }$ plane for $e^{+}{e}^{-}\to \gamma \gamma e^{+}{e}^{-}$ induced by ALP at 240 GeV and 91 GeV CEPC with designed luminosities.

Figure 9

The 95% C.L. exclusion regions on the ALP couplings $g_{a\gamma \gamma }$ as function of $M_a$ from the process $e^{+}{e}^{-}\to \gamma \gamma e^{+}{e}^{-}$ at the CEPC and other current exclusion regions.