  We report the results of the femtoscopic analysis of pairs of identical pions
measured in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV. Femtoscopic
radii are determined as a function of event multiplicity and pair momentum in
three spatial dimensions. As in the pp collision system, the analysis is
complicated by the presence of sizable background correlation structures in
addition to the femtoscopic signal. The radii increase with event multiplicity
and decrease with pair transverse momentum. When taken at comparable
multiplicity, the radii measured in p-Pb collisions, at high multiplicity and
low pair transverse momentum, are 10-20% higher than those observed in pp
collisions but below those observed in A-A collisions. The results are compared
to hydrodynamic predictions at large event multiplicity as well as discussed in
the context of calculations based on gluon saturation.

Nuclear Experiment