Estimation of backgrounds from jets misidentified as τ-leptons using the Universal Fake Factor method with the ATLAS detector


Zwalinski L., Zou W., Zormpa O., Zorbas T., Zoch K., Zoccoli A., ...Daha Fazla

European Physical Journal C, cilt.85, sa.12, 2025 (SCI-Expanded, Scopus) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 85 Sayı: 12
  • Basım Tarihi: 2025
  • Doi Numarası: 10.1140/epjc/s10052-025-14916-1
  • Dergi Adı: European Physical Journal C
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Compendex, INSPEC, zbMATH, Directory of Open Access Journals, Nature Index
  • Ankara Üniversitesi Adresli: Evet

Özet

Processes with τ-leptons in the final state are important for Standard Model measurements and searches for physics beyond the Standard Model. The ATLAS experiment at the Large Hadron Collider observes τ-leptons produced in proton–proton collisions only through their decay products. Data analyses involving hadronically decaying τ-leptons face challenges due to backgrounds from jets misidentified as τ-leptons that are not modelled reliably by Monte Carlo simulations. Data-driven methods such as the fake-factor method allow such misidentified backgrounds to be predicted by measuring transfer factors, known as fake factors, in data from dedicated regions. This paper describes a refined technique for determining the fake factors, the Universal Fake Factor method. It evaluates the fake factors for a signal region by using fake factors from samples enriched in different sources of jets misidentified as τ-leptons (light-quark, gluon, b-quark, and pile-up jets). Each fake factor is calculated as a linear combination of fake factors measured in these different enriched samples. For the full Run 2 data set, the systematic uncertainty of the calculated fake factors, evaluated using W(μν) enriched event sample, ranges from 15 to 35% depending on the τ-lepton’s transverse momentum and charged-particle decay multiplicity.