No light shining through a wall : new results from a photoregeneration experiment

TL;DR

The 2sigma limits obtained so far are presented and it is found that the axionlike particle two photons inverse coupling constant M is >8 x 10{5} GeV provided that the particle mass m{a} approximately 1 meV.

Abstract

Recently, axion-like particle search has received renewed interest. In particular, several groups have started ``light shining through a wall'' experiments based on magnetic field and laser both continuous, which is very demanding in terms of detector background. We present here the 2$σ$ limits obtained so far with our novel set-up consisting of a pulsed magnetic field and a pulsed laser. In particular, we have found that the axion-like particle two photons inverse coupling constant $M$ is $> 8\times 10^5$ GeV provided that the particle mass $m_\mathrm{a} \sim$ 1 meV. Our results definitively invalidate the axion interpretation of the original PVLAS optical measurements with a confidence level greater than 99.9%.

Figures (4)

• Figure 1: Scheme of our experimental setup.
• Figure 2: Magnetic field $B_0$ at the center of the magnet as a function of time. The maximum is reached within 1.75 ms and can be considered as constant ($\pm 0.3\%$) during $\tau_{B} = 150\,\mu$s. The 5 ns laser pulse is applied during this interval. Inset: Temporal profile of the laser pulse.
• Figure 3: Coincidence rate between the arrival of photons on the detector and its 5 ns detection gate as a function of an arbitrary delay time. The arrow indicates our working point, chosen in order to maximize the coincidence rate.
• Figure 4: 95% confidence level limits on the axion-like particle two photons inverse coupling constant $M$ as a function of the axion-like particle mass $m_\mathrm{a}$ obtained thanks to our null result (dotted line). The area below our curve is excluded. Our limits are compared to the $95\,\%$ confidence level exclusion region obtained by the BFRT photon regeneration experiment BNL1993.