Search for exotic low-mass fields with a global magnetometer network

The Global Network of Optical Magnetometers for Exotic physics searches (GNOME) is a network of geographically separated, time-synchronized, optically pumped atomic magnetometers searching for correlated transient signals that might herald exotic physics [1]. Quantum sensor networks provide an additional tool in multi-messenger astronomy to probe high-energy astrophysical events for signals by beyond-standard-model theories. We present a method to use the GNOME to search for coherent, intense bursts of exotic low-mass fields (ELFs) that could be produced alongside gravitational waves (GWs) [2]. Candidate events are first identified with a model agnostic excess power search [3] and then subjected to a generalized likelihood test. We construct Feldman-Cousins confidence belts [4] to constrain detectable ELF signal amplitudes and couplings to standard-model fermions. We report the first results of the method for the GW event S200311bg [5] detected by LIGO and Virgo.