Recent measurements in two-particle correlations in $p$+Pb collisions suggest collective behavior reminiscent of that observed in Pb+Pb. Femtoscopic measurements may provide useful insight on this behavior because they image the spatio-temporal size of the particle emitting region. This proceeding presents identical-pion Hanbury Brown and Twiss (HBT) measurements from ATLAS using one- and three-dimensional correlation functions. Pions are identified using $\text{ d}E/\text{ d}x$ measured in the pixel detector. Correlation functions and the resulting HBT radii are shown as a function of pair momentum ($k_{ \rm T}$) and collision centrality.
Categories: nucl-ex