  A rapidity gap trigger for the ALICE detector at the Large Hadron Collider
LHC is presented and a few selected physics observables are discussed. First,
some properties of double pomeron events are outlined. Second, signatures of
the odderon in diffractive J/Psi production is discussed. Third, possible
evidence of gluon saturation in the cross section of diffractive heavy quark
photoproduction is investigated.
