tWH associated production at the LHC

Abstract

We study Higgs boson production in association with a top quark and a W boson at the LHC. At NLO in QCD, tWH interferes with and a procedure to meaningfully separate the two processes needs to be employed. In order to define tWH production for both total rates and differential distributions, we consider the diagram removal and diagram subtraction techniques that have been previously proposed for treating intermediate resonances at NLO, in particular in the context of tW production. These techniques feature approximations that need to be carefully taken into account when theoretical predictions are compared to experimental measurements. To this aim, we first critically revisit the tW process, for which an extensive literature exists and where an analogous interference with production takes place. We then provide robust results for total and differential cross sections for tW and tWH at 13 TeV, also matching short-distance events to a parton shower. We formulate a reliable prescription to estimate the theoretical uncertainties, including those associated to the very definition of the process at NLO. Finally, we study the sensitivity to a non-Standard-Model relative phase between the Higgs couplings to the top quark and to the W boson in tWH production.

Automated simulations beyond the Standard Model: supersymmetry

“…In the latter spin-2 case, new physics have also been previously explored in a semi-automated framework (in the sense where the virtual matrix elements are provided externally) based on MG5 aMC [174][175][176]. Various BSM setups in which the Higgs sector differs from the SM one have been released, such as the two-Higgs-doublet model [177,178], the Georgi-Machacek model [179], the Higgs characterisation model [180][181][182][183][184], and the SM effective field theory including dimension-six operators [185]. Higherdimension operators either affecting the sector of the top quark [186][187][188][189][190][191], dijet production [192], or Z-boson production [193] can be added as well.…”

“…We also point out that in the NLO+PS simulations of ref. [184] a third scenario has been considered (dubbed DR2 there, and originally introduced in ref. [116] within a fixed-order calculation), in which one keeps the second term on the r.h.s.…”

“…We describe those implemented in MG5 aMC below, and point out that previous results in the DS approach [142,143,148,149,215,[223][224][225] have been obtained with a given (f, P) pair (with the exception of ref. [184], where two different forms of f have been compared).…”

Constraining new physics from Higgs measurements with Lilith: update to LHC Run 2 results

“…Most of this is based on the database release DB 19.06 (June 2019). Three ATLAS results (HIGG-2017-14, HIGG-2016-10 and HIGG-2018-54) were added to this during the peer-review process, so that the current latest version is DB 19…”

Theory overview for ttH and tH production

“…The dominant production mode at the LHC is in the t-channel, while the s-channel mechanism has a very small cross-section (σ s tH ≃ 3 fb). A third production mechanism is tHW production, with a cross-section σ tHW ≃ 20 fb [58,59]. In what follows, I will focus on the t-channel production mechanism.…”