https://doi.org/10.1140/epjc/s10052-019-6746-z
Regular Article - Theoretical Physics
Associated production of a top quark pair with a heavy electroweak gauge boson at NLO+NNLL accuracy
1
Institute for Theoretical Physics, WWU Münster, 48149, Münster, Germany
2
Institute of Physics, Jagiellonian University, S.Łojasiewicza 11, 30-348, Kraków, Poland
3
Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342, Kraków, Poland
4
Physics Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
5
Institute for Theoretical Physics, Georg-August-Univesity Göttingen, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany
6
Institut de Physique Théorique, Paris Saclay University, CEA, CNRS, 91191, Gif-sur-Yvette, France
* e-mail: anna.kulesza@uni-muenster.de
Received:
7
January
2019
Accepted:
27
February
2019
Published online:
20
March
2019
We perform threshold resummation of soft gluon corrections to the total cross sections and the invariant mass distributions for production of a top-antitop quark pair associated with a heavy electroweak boson 
, 
or Z in pp collisions at the Large Hadron Collider. The resummation is carried out at next-to-next-to-leading-logarithmic (NNLL) accuracy using the direct QCD Mellin space technique in the three-particle invariant mass kinematics. It is found that for the 
process the soft gluon resummation introduces significant corrections to the next-to-leading order (NLO) results. For the central scale equal to the invariant mass the corrections reach nearly 30%. For this process, the dominant theoretical uncertainty of the cross section due to the scale choice is significantly reduced at the NLO+NNLL level with respect to the NLO results. The effects of resummation are found to be less pronounced in the 
case. The obtained results are compared to recent measurements performed by CMS and ATLAS collaborations at the LHC.
© The Author(s), 2019
