Electron--electron correlations assessed analyzing doubly differential angular distributions in double ionization of helium by proton impact

Double ionization (DI) of helium by ion impact presents a singular scenario to study electron-electron correlation in atomic physics. Recent experimental data have revealed signatures of this feature in the doubly differential cross sections in terms of the angles of the two emitted electrons [1]. We present an exhaustive theoretical and experimental study of these cross sections, by disentangling the contribution of the different mechanisms that contribute to DI [2]. To this end, first order and higher order distorted wave theories are implemented jointly with the Monte Carlo Event Generator method (MCEG) [3]. This latter tool allows us to incorporate efficiently all the experimental conditions in the theoretical models. [1] M. Schulz et al, J. Phys. B \textbf{38}, 1363-1370 (2005). [2] M. F. Ciappina et al, PRA (in preparation) (2008). [3] M. D\"{u}rr et al, Phys. Rev. A \textbf{75}, 062708 (2007).