Dortmund 2021 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

T: Fachverband Teilchenphysik

T 5: Higgs decay in fermions I

T 5.6: Vortrag

Montag, 15. März 2021, 17:15–17:30, Te

Search for resonant HH → 4τ production with the ATLAS detector — •Dominik Weiß, Henrik Junkerkalefeld, Christian Grefe, Philip Bechtle, and Klaus Desch — Physikalisches Institut, Universität Bonn, Deutschland

Although with the discovery of the Higgs boson in 2012 all particles predicted by the Standard Model (SM) have been found, there are still a few SM parameters which have not been measured yet. The Higgs self-coupling strength, which actually has not been measured directly at all, is one of these parameters that is very sensitive to many extensions beyond the SM as well.

In this talk we will discuss the prospects of measuring the Higgs self-coupling in the 4τ final state and of using it to search for new beyond SM X → HH resonances . In order to increase the sensitivity of this measurement, several channels have to be combined. In addition to the ones already studied, the HH→ 4τ channel provides a unique final state with up to four hadronically decaying τ-leptons, which can be efficiently distinguished from most other SM background processes. Due to the very low cross section of HH production, a high selection efficiency is of utmost importance. A dedicated identification method for multi-tau events based on multiplied τ-lepton probabilities has been developed and tested on ATLAS Run 2 data. A measurement of the ZZ→ 4τ process is used to validate the identification of a signal with four true τ-leptons. An estimate of the largest background due to QCD jets misidentified as τ-lepton decay using combinatorial considerations of the reconstructed four τ-lepton charges will be discussed as well.