Search for Axionlike and Scalar Particles with the NA64 Experiment

Abstract

We carried out a model-independent search for light scalar (s) and pseudoscalar axionlike (a) particles that couple to two photons by using the high-energy CERN SPS H4 electron beam. The new particles, if they exist, could be produced through the Primakoff effect in interactions of hard bremsstrahlung photons generated by 100 GeV electrons in the NA64 active dump with virtual photons provided by the nuclei of the dump. The a(s) would penetrate the downstream HCAL module, serving as shielding, and would be observed either through their $a(s)\to \gamma \gamma$ decay in the rest of the HCAL detector or as events with large missing energy if the a(s) decays downstream of the HCAL. This method allows for the probing the a(s) parameter space, including those from generic axion models, inaccessible to previous experiments. No evidence of such processes has been found from the analysis of the data corresponding to $2.84\times 10^{11}$ electrons on target allowing to set new limits on the $a(s)\gamma \gamma$-coupling strength for a(s) masses below 55 MeV.

This publication is dedicated to the memory of our colleague Danila Tlisov. 7 pages, 5 figures, revised version accepted for publication in Phys. Rev. Lett

References in corpus (5)

• Measurement of the fine-structure constant as a test of the Standard Model
• Revised constraints and Belle II sensitivity for visible and invisible axion-like particles
• Redefining the Axion Window
• Contributions of axion-like particles to lepton dipole moments
• Search for invisible decays of sub-GeV dark photons in missing-energy events at the CERN SPS

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