Introduction

Electron reconstruction in ATLAS combines the information from the Inner detector and the electromagnetic calorimeter. The electron identification and trigger efficiencies are crucial for benchmark processes W,Z in early data.

The Tag-and-Probe Method

Comments on the InsituPerformance framework.

Selection Criteria

Fit Signal and Background

Extended Maximum Likelihood (EML) :

Breit-Wigner: $BW(M_Z, \Gamma_Z; M_{ee}) = \frac{\Gamma_Z}{2\pi} \frac{1}{(M_{ee} - M_Z)^2 + \Gamma_Z^2}$

Approximate parton luminosity term: $( \frac{M_Z}{M_{ee}} )^\beta$

Crystal Ball: $$A$$

Introduction

The Tag-and-Probe Method

Selection Criteria

Fit Signal and Background

Datasets

Results

Systematics