Bonn 2020 – scientific programme
The DPG Spring Meeting in Bonn had to be cancelled! Read more ...
Parts | Days | Selection | Search | Updates | Downloads | Help
T: Fachverband Teilchenphysik
T 88: Top quarks: associated production
T 88.9: Talk
Thursday, April 2, 2020, 18:30–18:45, L-4.001
Search for tttt production in same-sign dilepton and multilepton final states at the LHC with the ATLAS detector using the full Run-2 dataset — •Ö. Oğul Öncel, Niklas W. Schwan, and Markus Cristinziani — Universität Bonn
Production of tttt in proton–proton collisions is a rare process predicted by the Standard Model with an expected cross section of around 0.01 pb. Many BSM theories, such as Top Compositeness and 2HDM, predict an enhancement of the tttt cross section. In addition, tttt can also be used to measure the top-quark Yukawa coupling, another important quantity for probing new physics.
A search for this process in the same-sign dilepton and multilepton channels using ATLAS data collected at the LHC during 2015–2018 with 139.4 fb−1 integrated luminosity and at a centre-of-mass energy of 13 TeV, is presented. The main challenges are the small cross section, irreducible background contaminations from ttZ, ttW, ttH, as well as sizeable backgrounds due to charge mis-identification and photon conversion. Particular focus is given to the multi-variate techniques used in signal extraction, which has led to significant improvement in the signal sensitivity.