scholarly journals Global and optimal probes for the top-quark effective field theory at future lepton colliders

2018 ◽  
Vol 2018 (10) ◽  
Author(s):  
Gauthier Durieux ◽  
Martín Perelló ◽  
Marcel Vos ◽  
Cen Zhang
2019 ◽  
Vol 2019 (4) ◽  
Author(s):  
Nathan P. Hartland ◽  
Fabio Maltoni ◽  
Emanuele R. Nocera ◽  
Juan Rojo ◽  
Emma Slade ◽  
...  

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
T. Bergauer ◽  
...  

Abstract Events containing one or more top quarks produced with additional prompt leptons are used to search for new physics within the framework of an effective field theory (EFT). The data correspond to an integrated luminosity of 41.5 fb−1 of proton-proton collisions at a center-of-mass energy of 13 TeV at the LHC, collected by the CMS experiment in 2017. The selected events are required to have either two leptons with the same charge or more than two leptons; jets, including identified bottom quark jets, are also required, and the selected events are divided into categories based on the multiplicities of these objects. Sixteen dimension-six operators that can affect processes involving top quarks produced with additional charged leptons are considered in this analysis. Constructed to target EFT effects directly, the analysis applies a novel approach in which the observed yields are parameterized in terms of the Wilson coefficients (WCs) of the EFT operators. A simultaneous fit of the 16 WCs to the data is performed and two standard deviation confidence intervals for the WCs are extracted; the standard model expectations for the WC values are within these intervals for all of the WCs probed.


2011 ◽  
Vol 704 (3) ◽  
pp. 218-222 ◽  
Author(s):  
Nicolas Greiner ◽  
Scott Willenbrock ◽  
Cen Zhang

2016 ◽  
Vol 2016 (5) ◽  
Author(s):  
Olga Bessidskaia Bylund ◽  
Fabio Maltoni ◽  
Ioannis Tsinikos ◽  
Eleni Vryonidou ◽  
Cen Zhang

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
◽  
N. Tonon ◽  
H. Aarup Petersen ◽  
M. Aldaya Martin ◽  
P. Asmuss ◽  
...  

Abstract A search for new top quark interactions is performed within the framework of an effective field theory using the associated production of either one or two top quarks with a Z boson in multilepton final states. The data sample corresponds to an integrated luminosity of 138 fb−1 of proton-proton collisions at $$ \sqrt{s} $$ s = 13 TeV collected by the CMS experiment at the LHC. Five dimension-six operators modifying the electroweak interactions of the top quark are considered. Novel machine-learning techniques are used to enhance the sensitivity to effects arising from these operators. Distributions used for the signal extraction are parameterized in terms of Wilson coefficients describing the interaction strengths of the operators. All five Wilson coefficients are simultaneously fit to data and 95% confidence level intervals are computed. All results are consistent with the SM expectations.


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