Study of Bose-Einstein correlations ine+e−annihilation at 29 GeV

Bose-Einstein correlations between like-sign pions have been investigated in $e^{+}$ $e^{\mathrm{-}}$ annihilation at √s =29 GeV using the Time Projection Chamber detector at the SLAC $e^{+}$ $e^{\mathrm{-}}$ storage ring PEP. The production rate of like-sign pion pairs with small relative momentum is found to be increased by more than 50% over the rate expected for uncorrelated production of pions. From the correlation length, a typical source radius of 0.65 fm is derived. Data are consistent with a spherical shape of the pion source. No dependence of radius or correlation strength on the event multiplicity is observed.