Collisions of protons with light nuclei shed new light on nucleon structure

The high rates of multiparton interactions at the LHC can provide a unique opportunity to study the multiparton structure of the hadron. To this purpose high-energy collisions of protons with nuclei are particularly suitable. The rates of multiparton interactions depend, in fact, both on the partonic multiplicities and on the distributions of partons in transverse space, which produce different effects on the cross section in pA collisions, as a function of the atomic mass number A. Differently with respect to the case of multiparton interactions in pp collisions, the possibility of changing the atomic mass number thus provides an additional handle to distinguish the diverse contributions. Some relevant features of double parton interactions in pD collisions have been discussed in a previous paper. In the present paper we show how the effects of double and triple correlation terms of the multiparton structure can be disentangled, by comparing the rates of multiple parton interactions in collisions of protons with D, H-3, and He-3.