Search for pair and single production of vector-like quarks decaying to a Z boson in pp collisions at 13 TeV with data collected with the ATLAS detector

Jun 5, 2018, 4:00 PM
1h 30m
Library, Centro San Domenico

Library, Centro San Domenico

LHC experiments Posters session


Elena Murielle Freundlich (Technische Universitaet Dortmund (DE))


A search for pair and single production of vector-like quarks T and B with a leptonically decaying Z boson is presented. The data were collected in pp collisions at 13 TeV with the ATLAS detector at the Large Hadron Collider, corresponding to an integrated luminosity of 36.1 fb$^{-1}$. A high momentum Z boson is reconstructed from a same-flavor pair of leptons, which carry opposite charge, and are created alongside a third generation quark, conserving the charge of vector-like T (q_T=+2/3) and B (q_B=-1/3) quarks. Final states with different multiplicities of leptons, large-R jets and b-tagged small-R jets alongside other selection criteria are used to discriminate the signal from background processes. Five channels are optimized on a topology with high object momenta and are then combined for pair and for single production separately. No excess above the Standard model expectation was found, which is why lower mass limits on vector-like T and B quarks at a 95% confidence level are derived for the singlet and doublet model. In case of the single production also limits on the coupling to the Standard Model quarks are set.

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