Recent Results from the Strong Interaction Program of the NA61/SHINE Experiment and Physics Plans Beyond 2020

The NA61/SHINE experiment at the CERN SPS studies hadron production properties in hadron-nucleus and nucleus–nucleus collisions. The experiment performs unique measurements for physics of strong interactions as well as important measurements for neutrino and cosmic-ray physics. Results from the strong interaction programme indicate a threshold for formation of large clusters interpreted as the onset of fireball. A scaled-factorial-moment analysis of the proton density fluctuations in Ar+Sc collisions at 150A GeV/$\mathit{c}$ shows an intermittency signal, which may be a first trace of critical behavior. The main objective of the future NA61/SHINE program is to obtain high-precision data on charm hadron production. This new program is planned to start after 2020 and requires significant upgrades of the NA61/SHINE detector setup. Besides the construction of a large acceptance vertex detector, a 10-fold increase of the event recording rate is foreseen.