Analysis of wave packet interference pattern in Young experiment

Since its beginning the quantum mechanics has been so controversial theory, that not all physicist ware able to agree with its assumptions. Nowadays it seems that the problem does not exist any more, although the quantum theory is still incomplete. The main point of the discussion, which has been risen all the time, is the problem of the measurement understood as the influence of the observer or the detector presence on the wave pocket describing the state of the observed system. In this paper the problem of the detector influence on the state of the system is reported on the basis of two-slit experiment described in new formalism called projection evolution. This new approach connects two ways of state evolution: unitary evolution and evolution visible during the measurement.