Search for photon oscillations into massive particles

TL;DR

This work addresses the laboratory search for light weakly coupled bosons by testing photon oscillations into axion-like particles and paraphotons using a two-magnet, wall setup at LULI. The authors derive the pertinent oscillation and regeneration probabilities, implement a high-sensitivity, pulsed photoregeneration experiment with synchronized laser, magnetic field, and detector, and perform a final null result. The study sets stringent limits: $M>9.1\times10^{5}$ GeV for low-mass axion-like particles and $\chi<1.1\times10^{-6}$ (with an enhanced $\chi<1.9\times10^{-7}$ at $\mu=\omega$) for paraphotons, improving prior terrestrial bounds and excluding the PVLAS scenario. These results constrain low-mass hidden-sector physics and illustrate the potential of precision optical experiments to probe beyond-Standard Model theories in the low-energy window; future facilities like BMV and ELI could extend these limits and explore related fields such as chameleons.

Abstract

In this paper, we present the final results of our experiment on photon-axion oscillations in the presence of a magnetic field, which took place at LULI (Laboratoire pour l'Utilisation des Lasers Intenses, Palaiseau, France). Our null measurement allowed us to exclude the existence of axions with inverse coupling constant $M>9.\times 10^5$ GeV for low axion masses and to improve the preceding BFRT limits by a factor 3 or more for axion masses $1.1 {meV} <m_a<2.6 {meV}$. We also show that our experimental results improve the existing limits on the parameters of a low mass hidden-sector boson usually dubbed "paraphoton" because of its similarity with the usual photon.

Figures (14)

• Figure 1: Sketch of the apparatus. The wall and the blind flanges are removable for fibre alignment.
• Figure 2: Focal spot without correction(a) and with wave-front correction (b). This correction allows to maintain a spot of one or two diffraction limits despite the amplifiers' not being in thermal equilibrium.
• Figure 3: Number of high energy pulses versus laser energy during the four weeks of data acquisition.
• Figure 4: Scheme of XCoil. Magnetic fields $\vec{B_1}$ and $\vec{B_2}$ are created by each of the race-track shaped windings. This yields a high transverse magnetic field $\vec{B}$ while allowing the necessary optical access for the laser photons $\gamma$.
• Figure 5: Transverse magnetic field inside the magnet along the laser direction. At the center of the magnet we have a mean maximum magnetic field $B_0 = 12$ T. Integrating $B$ along the optical path yields 4.38 T.m.