  In this paper we show how effective parameters such as effective binding
energies can be defined for a proton in the combined nuclear-Coulomb potential,
including also the target potential, in the case in which the proton is bound
in a nucleus which is partner of a nuclear reaction. Using such effective
parameters the proton behaves similarly to a neutron. In this way some
unexpected results obtained from dynamical calculations for reactions initiated
by very weakly bound proton halo nuclei can be interpreted. Namely the fact
that stripping dominates the nuclear breakup cross section which in turn
dominates over the Coulomb breakup even when the target is heavy at medium to
high incident energies. Our interpretation helps also clarifying why the
existence and characteristics of a proton halo extracted from different types
of data have sometimes appeared contradictory.
