Seminar: "Electron identification with ATLAS at the LHC (Asma Hadef)

Datum

19.10.2023

Zeit

15:00 - 16:00

Sprache

en

Hauptthema

Willkommen

Andere Themen

Physik, Willkommen

Beschreibung

Electrons are important objects both for the search for new physics and for precision measurements. In the ATLAS detector, electrons in the central detector region (|η| < 2.47) are triggered by and reconstructed from energy deposits in the electromagnetic (EM) calorimeter that are matched to a track in the inner detector. Electrons are distinguished from other particles using identification (ID) criteria with different levels of background rejection and signal efficiency. The ID criteria rely on the shapes of EM showers in the calorimeter as well as on tracking quantities and the quality of the matching of the tracks to the clustered energy deposits in the calorimeter. The electron ID used in ATLAS for Run 2 is based on a likelihood discrimination to separate isolated electron candidates from candidates originating from photon conversions, hadron misidentification and heavy flavor decays. In Run3, an algorithm to identify electrons in the ATLAS experiment based on a deep neural network was recently developed. Depending on the kinematics of the electron candidate, an increase in background rejection between 1.7 and 5.5 at the same signal efficiency can be observed. The performance of the electron ID algorithms is evaluated by measuring efficiencies using tag-and-probe techniques with large statistics samples of isolated electrons from  Z→ee and J/ψ→ee resonance decays. These measurements were performed with pp collisions data at √s=13 TeV in 2015-2018 corresponding to an integrated luminosity of 139 fb−1 and studied as a function of the electron’s transverse momentum, pseudorapidity and number of primary vertices. The first results of Run3 data recorded in 2022 from pp collisions at √s=13.6 TeV, corresponding to an integrated luminosity of 3.4 fb−1, will also be presented. Furthermore, in order to achieve reliable physics results, the simulated samples need to be corrected to reproduce the measured data efficiencies as closely as possible. For this reason, the efficiencies are estimated both in data and in simulation. The scale factors (data to MC efficiency ratios) are then estimated and provided to all physics analyses involving electrons.

Links

• Termindetails auf den Webseiten der TU Dresden (https://tu-dresden.de)

Letztmalig verändert: 19.10.2023, 07:40:57