Light and charge yields from nuclear recoils in noble liquids: From sub-keV energies to 1 MeV

Abstract

We present a first-principles study of total quanta and charge recombination in noble liquids, based on a solution of Lindhard's integro-differential equation for atomic motion with electronic straggling and detailed modeling of inter-atomic potentials. We introduce the electronic scaling length $ξ_e$ as a fundamental parameter related to a physical observable of the system. We study the energy and electric-field dependence of the exciton-to-ion ratio for nuclear recoils based on the Bates-Griffing process and semiclassical atomic interactions. The resulting light and charge yields are expressed through the recombination probability in the Thomas-Imel box model using the calculated parameter $ξ_e$ and one fitted constant. We compare our model with recent measurements of the electric-field dependence of the box size in LAr and LXe and provide a physical explanation for this behavior. Our model extends to sub-keV energies and provides a consistent description of available data from a few keV to 1 MeV, yielding better overall agreement with existing LAr data than NEST and offering predictions for LXe.