IFLP   13074
INSTITUTO DE FISICA LA PLATA
Unidad Ejecutora - UE
artículos
Título:
Measurement of the tt¯Z and tt¯W cross sections in proton-proton collisions at s√=13 TeV with the ATLAS detector
Autor/es:
ATLAS COLL. M. AABOUD, F. ARDUH ET AL
Revista:
PHYSICAL REVIEW D
Editorial:
AMER PHYSICAL SOC
Referencias:
Lugar: New York; Año: 2019
ISSN:
1550-7998
Resumen:
A measurement of the associated production of a top-quark pair (tt¯) with a vector boson (W, Z) in proton-proton collisions at a center-of-mass energy of 13 TeV is presented, using 36.1  fb-1 of integrated luminosity collected by the ATLAS detector at the Large Hadron Collider. Events are selected in channels with two same- or opposite-sign leptons (electrons or muons), three leptons or four leptons, and each channel is further divided into multiple regions to maximize the sensitivity of the measurement. The tt¯Z and tt¯W production cross sections are simultaneously measured using a combined fit to all regions. The best-fit values of the production cross sections are σtt¯Z=0.95±0.08stat±0.10syst  pb and σtt¯W=0.87±0.13stat±0.14syst  pb in agreement with the Standard Model predictions. The measurement of the tt¯Z cross section is used to set constraints on effective field theory operators which modify the tt¯Z vertex.