Transverse momentum versus multiplicity fluctuations in high-energy nuclear collisions

We discuss recently measured event-by-event fluctuations of transverse momentum and of multiplicity in relativistic heavy-ion collisions. It is shown that the nonmonotonic behavior of the p_T fluctuations as a function of collision centrality can be fully explained by the observed nonmonotonic multiplicity fluctuations. A possible mechanism responsible for the multiplicity fluctuations is also considered.