Speaker
Description
We present a formalism for describing atomic collision cascades in crystalline silicon
and germanium, based on a second-order solution to the Lindhard integral equation.
We analyze in detail how the traditional Lindhard formula is only applicable for energies
above 10 keV. Below this threshold, the omission of atomic binding energy, kinematic effects,
and the breakdown of electronic stopping approximations lead to inaccurate predictions
of ionization yield. We describe in detail the physical aspects of these low-energy interactions,
paying particular attention to the novel ionization channels. This formalism is used to derive
two general theoretical constraints that reconcile recent and contradictory experimental
measurements of the quenching factor. Furthermore, we characterize the statistical fluctuations
of the ionization process by solving the integral equation for the second moment, which formally
introduces the nuclear Fano factor. We analyse how the nuclear Fano factor is a relevant
parameter for coherent elastic neutrino-nucleus scattering (CE(\nu)NS) studies and for
constraining new physics, such as the magnetic moments of neutrinos and light mediators,
using high-precision CE(\nu)NS data