  We present a dynamical explanation of the hollowness effect observed in
proton-proton scattering at $\sqrt s\!=\!7$ TeV. This phenomenon, not observed
at lower energies, consists in a depletion of the inelasticity density at zero
impact parameter of the collision. Our analysis is based on three main
ingredients: we rely gluonic hot spots inside the proton as effective degrees
of freedom for the description of the scattering process. Next we assume that
some non-trivial correlation between the transverse positions of the hot spots
inside the proton exists. Finally we build the scattering amplitude from a
multiple scattering, Glauber-like series of collisions between hot spots. In
our approach, the onset of the hollowness effect is naturally explained as due
to the diffusion or growth of the hot spots in the transverse plane with
increasing collision energy.
