Effects of breakup thresholds in the single-particle momentum distributions of a few-body continuum

We present an alternative approach for the study of a break-up process at threshold. Specifically, we demonstrate that the single differential cross section of one particle in a few-body system carries basic information about the breakup threshold of the remaining cluster. Thus, it represents an alternative approach for the study of few-body continua at very low energies. We exemplify these ideas by analyzing the particular case of a three-body system. In particular, we show that it is possible to extract electron-atom scattering parameters, such as the s-wave scattering length from ionization measurements.