[en] Inclusive coherent proton diffraction dissociation on helium has been measured in the four-momentum transfer and missing-mass region 0.04< Vertical BartVertical Bar<0.40 (GeV/c)², M/sub X//sup ts2/<10 GeV² and for incident proton beam momenta from 46 to 400 GeV/c. We find that the differential cross section d²s/dt dM/sub X//sup ts2/ varies slowly with energy, reveals a pronounced peak at M/sub X//sup ts2/approx. =2 GeV², and at large masses behaves approximately as 1/M/sub X//sup ts2/. The cross section falls exponentially as Vertical BartVertical Bar increases, with a large slope parameter at small momentum transfers and a substantially smaller one at large Vertical BartVertical Bar values, with no clear dip between the two regions as seen in elastic scattering. We compare the experimental t distributions to Glauber-model predictions and find the data provide a sensitive test of the assumptions on the details of the elementary proton diffraction-dissociation amplitudes and on the total cross sections of the diffractively produced states