Search for Axionlike and Scalar Particles with the NA64 Experiment
Search for Axionlike and Scalar Particles with the NA64 Experiment
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 …