Search for sub-eV axion-like particles in a stimulated resonant photon-photon collider with two laser beams based on a novel method to discriminate pressure-independent components

Abstract

Sub-eV axion-like particles (ALPs) have been searched for by focusing two-color near-infrared pulse lasers into a vacuum along a common optical axis. Within the focused quasi-parallel collision system created by combining a creation field (2.5 mJ/47 fs Ti:Sapphire laser) and a background inducing field (1.5 mJ/9 ns Nd:YAG laser), the detection of signal photons via stimulated resonant photon-photon scattering by exchanging ALPs was attempted in a vacuum chamber. The signal wavelength can be determined via energy-momentum conservation in the vacuum, and it coincides with that determined from the atomic four-wave-mixing (aFWM) process. In this work, the pulse energies were one order of magnitude higher than those in the previous search, allowing aFWM from optical elements to be observed as a pressure-independent background for the first time, in addition to the residual-gas-originating aFWM following a quadratic pressure dependence. In principle the four-wave-mixing process in vacuum via ALP exchanges (vFWM) must also be pressure-independent, so the development of a new method for discriminating the optical-element aFWM is indispensable for increasing the pulse energies to the values needed for future upgraded searches. In this paper, we will present the established method for quantifying the yield from the optical-element aFWM process based on the beam cross- section dependence. With the new method, the number of signal photons was found to be consistent with zero. We then successfully obtained a new exclusion region in the relation between ALP-photon coupling, g/M, and the ALP mass m, reaching the most sensitive point g/M = 1.14 × 10−5 GeV−1 at m = 0.18 eV.

Sensitivity to Axion-like Particles with a Three-Beam Stimulated Resonant Photon Collider around the eV Mass Range

“…So far, we have advocated a method to directly produce axion-like particles and simultaneously stimulate their decays by combining two-color laser fields in collinearly focused geometry [7]. This quasi-parallel photon-photon collision system has been dedicated to sub-eV axion mass window and the searches have been actually performed [8][9][10][11][12]. Given the axion mass window above eV and a typical laser photon energy of ∼1 eV, stimulated photon-photon collisions with different collision geometry has a potential to be sensitive to a higher mass window.…”

Feebly-interacting particles: FIPs 2020 workshop report

“…Figure50: Summary of current bounds and prospects of ongoing and future searches for the axion-photon coupling. Regions shaded in colours correspond to experiments: mauve for laboratory[498,499,706,707,713,714,715] and collider[703,741,185,742,743,185,744,745,746,747,748,749,749,750,751] searches for axions, green for searches for solar axions[236,158], and blue for direct dark matter detection experiments[752,667,505,507,561,661,290,285,288,753,289,276,676,754,402,689,508,509,691,704,755,664,511,708, 677,…”