First constraint on coherent elastic neutrino-nucleus scattering in argon

Coherent elastic neutrino-nucleus scattering (CEvNS), first predicted in the 1970s as part of the weak neutral current, has a distinctive cross-section depending on the square of the number of neutrons. The technical hurdles to its experimental observation are only now being overcome. In this paper, the COHERENT collaboration reports results from their engineering run with liquid argon that sets a new limit on CEvNS for this nucleus and confirms that they will have the sensitivity to observe it with their planned experiment program.