The electronic structure of InAs/GaAs self-assembled quantum dots and the carrier capture dynamics in these dots have been studied by magneto-photoluminescence at low temperature (5 K). We report results obtained on a series of samples processed by rapid thermal annealing. This intermixing procedure led to a significant narrowing of the inhomogeneous photoluminescence emission bands related to the various dot shell states, as compared to results obtained on unprocessed samples, which in turn improved the conditions for the observation of the Fock-Darwin energy levels structure as a function of the magnetic field, up to 15 T. We also observed that the ratio of the wetting layer emission intensity over the integrated intensity of the quantum dot emission bands increases nonlinearly with the magnetic field. This nonlinear behavior, which is more apparent at low photocarrier density, suggests that transport properties contribute to limit the carrier capture by the dots.