The distribution of electron waiting times is useful to characterize quantum
transport in mesoscopic structures. Here we consider a generic quantum-coherent
conductor consisting of a mesoscopic scatterer in a two-terminal setup. We
extend earlier results for single-channel conductors to setups with several
(possibly spin-degenerate) conduction channels and we discuss the effect of a
finite electronic temperature. We present detailed investigations of the
electron waiting times in a quantum point contact as well as in two mesoscopic
interferometers with energy-dependent transmissions: a Fabry-P\'erot
interferometer and a Mach-Zehnder interferometer. We show that the waiting time
distributions allow us to determine characteristic features of the scatterers,
for instance the number of resonant levels in the Fabry-P\'erot interferometer
that contribute to the electronic transport.Comment: 13 pages, 11 figure