Exploring pseudo-Nambu--Goldstone bosons by stimulated photon colliders in the mass range 0.1~eV to 10~keV

Understand

Searching for pseudo-Nambu--Goldstone bosons (pNGBs) in weak-coupling domains is crucial for understanding the dark components in the universe.

• We propose searching for pNGBs coupled to two photons in the mass range from 0.1~eV to 10~keV.
• This could provide opportunities to test string-theory-based pNGBs beyond the GUT scale $M \sim 10^{16}$~GeV included in the weak coupling proportional to $M^{-1}$.
• We provide formulae that are applicable to photon--photon scattering via a pNGB resonance exchange with a stimulation process in an asymmetric head-on photon--photon collider by mixing three laser pulses in laboratory experiments.