  The NA61/Shine experiment aims to discover the critical point of strongly
interacting matter and study the properties of the onset of deconfinement.
These goals are to be achieved by performing a two dimensional phase diagram
T-mu_B scan by measurements of hadron production properties in proton-proton,
proton-nucleus and nucleus-nucleus interactions as a function of collision
energy and system size. Close to the phase transition and/or close to the
critical point large fluctuations are predicted. In this contribution
preliminary results on two-particle correlations in pseudorapidity and
azimuthal angle will be presented for p+p interactions at beam momenta: 20, 31,
40, 80 and 158 GeV/c. The NA61/Shine results will be compared with the
corresponding data of other experiments and model predictions. A striking
evolution with collision energy is observed.
