Figure 1

(a) Transverse impact parameter ($d_{0}$) distributions of electrons from beauty and charm hadron decays, light hadron decays, and photon conversions obtained with PYTHIA 6 simulations in the electron $\pt$ range 1 $< \pt < $ 6 GeV/$c$, along with the measured distribution of conversion electrons. The distributions are normalized to the same integrated yield. (b) Ratios of the measured and simulated $d_{0}$ distributions of conversion electrons in the ranges 1 $< \pt < $ 6 GeV/$c$.