Stimulated radar collider for probing gravitationally weak coupling pseudo Nambu-Goldstone bosons

Abstract

We propose a stimulated pulsed-radar collider to directly produce pseudo Nambu-Goldstone bosons as candidates for dark components in the Universe and simultaneously induce the decay by mixing two radar beams. We have extended formulae for stimulated resonant photon-photon scattering in a quasi-parallel collision system by including fully asymmetric collision cases. With a pulse energy of 100 J in the GHz-band, for instance, which is already achieved by an existing klystron, we expect that the model-independent sensitivity can reach gravitationally weak coupling domains at a mass range 10−7–10−6 eV, if two key technological issues are resolved: pulse compression in time reaching the Fourier transform limit, and single-photon counting for GHz-band photons. Such testing might extend the present horizon of particle physics.

Search for sub-eV axion-like resonance states via stimulated quasi-parallel laser collisions with the parameterization including fully asymmetric collisional geometry

“…This stimulated resonant scattering rate eventually becomes proportional to the square of the number of photons in the creation laser beam and to the number of photons in the inducing laser beam. This cubic dependence on the number of photons in the beams offers opportunities to search for ALPs with extremely weak coupling when the beam intensity is high enough [27].…”

“…Therefore, we must accept a situation in which the incident photon energies and angles are both asymmetric. Recently, we formulated the interaction rate based on the fully asymmetric collision system [27], where the non-coaxial geometry of the two-photon collisions and stimulated decays are explicitly included with respect to a given coaxial geometry of focused beams (figure 2b).…”

“…However, if a collection of light waves is circularly polarized, we can avoid this complication because even if the directions of the waves in three dimensions are changed, the individual light waves retain the circular polarization. Therefore, in [27] we evaluated the stimulation effect based on circularly polarized laser beams. However, there is an experimental constraint in that high-intensity laser pulses are provided as linearly polarized states, and changing their polarization from linear to circular adds a technical difficulty.…”

“…Stimulated resonant photon-photon scattering in the most general collisional geometry including asymmetric incidence and non-coaxial scattering was formulated in [27], and the full details can be found in the appendix of [27]. In the following subsections, we briefly explain how to relate the physical parameters of mass m and coupling g/M with the observed number of stimulated photon signals by reviewing only the relevant formulae to discuss the interaction rate dedicated for this search.…”

“…In the following subsections, we briefly explain how to relate the physical parameters of mass m and coupling g/M with the observed number of stimulated photon signals by reviewing only the relevant formulae to discuss the interaction rate dedicated for this search. We specifically replace the vertex factors in the scattering amplitude because we must change from the circular polarization formulated in [27] to the linear one for both scalar and pseudoscalar field exchanges in this search.…”