# Two-pion Bose-Einstein correlations in pp collisions at $\sqrt{s}$=900 GeV

We report on the measurement of two-pion correlation functions from pp collisions at $\sqrt{s}$=900 GeV performed by the ALICE experiment at the Large Hadron Collider. Our analysis shows an increase of the HBT radius with increasing event multiplicity, in line with other measurements done in particle- and nuclear collisions. Conversely, the strong decrease of the radius with increasing transverse momentum, as observed at RHIC and at Tevatron, is not manifest in our data.

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## Figure 1

 Correlation functions for identical pions from $pp$ collisions at $\sqrt{s}$ = 900 GeV (full dots) and those obtained from a simulation using PHOJET (open circles). Positive and negative pion pairs were combined The three columns represent collisions with different charged-particlemultiplicities $M$; the transverse momentum of pion pairs $\kt~$(GeV/c) increases from top to bottom The lines going through the points represent the Gaussian fits discussed inthe text