Femtoscopy of $pp$ collisions at $\sqrt{s}=0.9$ and 7 TeV at the LHC with two-pion Bose-Einstein correlations
Phys.Rev. D84 (2011) 112004
The collaboration

Abstract (data abstract)
CERN-LHC. We report on the high statistics two-pion correlation functions from pp collisions at $\sqrt{s}$=0.9 TeV and $\sqrt{s}$=7 TeV, measured by the ALICE experiment at the Large Hadron Collider. The correlation functions as well as the extracted source radii scale with event multiplicity and pair momentum. When analyzed in the same multiplicity and pair transverse momentum range, the correlation is similar at the two collision energies.