production at NNLO: the flavour off-diagonal channels

Stefano Catani; Ignacio Fabre; Massimiliano Grazzini; Stefan Kallweit

doi:10.1140/epjc/s10052-021-09247-w

2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2021) 81: 491
https://doi.org/10.1140/epjc/s10052-021-09247-w

Regular Article - Theoretical Physics

$t \bar{t} H$ ${t {{\bar{t}}}H}$ production at NNLO: the flavour off-diagonal channels

Stefano Catani¹^,2, Ignacio Fabre³^,4, Massimiliano Grazzini³ and Stefan Kallweit⁵^,6^d

¹ INFN, Sezione di Firenze, Florence, Italy
² Dipartimento di Fisica e Astronomia, Università di Firenze, Sesto Fiorentino, 50019, Florence, Italy
³ Physik Institut, Universität Zürich, 8057, Zurich, Switzerland
⁴ International Center for Advanced Studies (ICAS), ICIFI and ECyT,Universidad Nacional de San Martin(UNSAM), 25 de Mayo y Francia (1650), Buenos Aires, Argentina
⁵ Dipartimento di Fisica, Università degli Studi di Milano-Bicocca, Milan, Italy
⁶ INFN, Sezione di Milano-Bicocca, 20126, Milan, Italy

^d stefan.kallweit@cern.ch

Received: 23 February 2021
Accepted: 17 May 2021
Published online: 2 June 2021

Abstract

We consider QCD radiative corrections to the associated production of a heavy-quark pair ( $Q \bar{Q}$ $Q{{\bar{Q}}}$ ) with a generic colourless system F at hadron colliders. We discuss the resummation formalism for the production of the $Q \bar{Q} F$ $Q{{\bar{Q}}}F$ system at small values of its total transverse momentum $q_{T}$ $$q_T$$ . We present the results of the corresponding resummation coefficients at next-to-leading and, partly, next-to-next-to-leading order. The perturbative expansion of the resummation formula leads to the explicit ingredients that can be used to apply the $q_{T}$ $$q_T$$ subtraction formalism to fixed-order calculations for this class of processes. We use the $q_{T}$ $$q_T$$ subtraction formalism to perform a fully differential perturbative computation for the production of a top-antitop quark pair and a Higgs boson. At next-to-leading order we compare our results with those obtained with established subtraction methods and we find complete agreement. We present, for the first time, the results for the flavour off-diagonal partonic channels at the next-to-next-to-leading order.

© The Author(s) 2021

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