Experimental constraint on an exotic spin- and velocity-dependent interaction with a spin-exchange relaxation-free magnetometer*

Many theoretical extensions of the Standard Model of particle physics suggested the existence of new hypothetical fundamental bosons to resolve the strong charge-parity (CP) problem in the quantum chromodynamics, such as the axion and axionlike particles. The exotic particles are very light and can mediate new macroscopic interactions between fermions with an interaction range from micrometers to centimeters. To explore exotic interactions, we recently proposed a novel experimental approach based on a spin-exchange relaxation-free (SERF) magnetometer, the most sensitive cryogen-free magnetic-field sensor reaching femto-Tesla sensitivity. This approach aims to sensitively detect magnetic-field-like effects from the exotic interactions between SERF polarized electrons and particles of an external solid-state mass. With our experimental approach, we conducted a search for an exotic spin- and velocity-dependent interaction between SERF polarized electrons and unpolarized nucleons. In this talk, we will report experimental results on the interaction with 82 hours of data averaging.