Observation of inclusive electrons in the ATLAS experiment at $\sqrt{s} = 7$ TeV.

This note presents the first observation of inclusive electrons in the collision data collected by the ATLAS experiment at $sqrt{s} =$ 7 TeV, corresponding to a total integrated luminosity of 13.8$\pm$1.5 nb$^{-1}$. From a sample of 67124 selected electron candidates, a signal of $9920 \pm 160$ (stat) $\pm 990$ (syst.) electrons, predominantly from heavy flavour production (semi-leptonic decays of charm and beauty hadrons), is extracted using a combination of particle identification techniques to determine the dominant hadron and conversion background contributions from data. This signal is compared to expectations from parton shower leading-order Monte Carlo simulations.