  In this talk we present the results of the investigation on the so called
double parton distribution functions (dPDFs), accessible quantities in high
energy proton-proton and proton nucleus collisions, in double parton scattering
processes (DPS). These new and almost unknown distributions encode information
on how partons inside a proton are correlated among each other and represent a
new tool to explore the three dimensional partonic structure of hadrons. In the
present contribution, results of the calculations of dPFDs are presented also
including phenomenological investigations on the impact of double correlations
in experimental observables, showing how the latter could be observed in the
next LHC run. In addition we discuss how present information on experimental
observables could be related to the transverse proton structure.
