Distributions and correlations for top quark pair production and decay at the Tevatron and LHC.

By W. Bernreuther, Zong-Guo Si. 2010

208 citations recorded by the source corpus.

Abstract We investigate a number of observables that are and will be instrumental in the exploration of t t ¯ production and decay at the Tevatron and the LHC. For this analysis we made a computer program that incorporates besides the NLO QCD corrections to t t ¯ production and decay also mixed weak-QCD corrections to the production amplitudes, and that allows for studies of correlated versus uncorrelated t t ¯ events. In this paper we analyze and compute observables mostly for dileptonic t t ¯ final states to next-to-leading order in the strong and weak gauge couplings (NLOW), with selection cuts. We calculate charge asymmetries of the top quark and of l = e , μ and we compare, where possible, with experimental results. We show that top-quark spin correlations affect a leptonic pair asymmetry (which has not been measured so far) by ∼7%. We determine several dileptonic angular correlations, which reflect t t ¯ spin correlations, namely the beam, off-diagonal and helicity correlation, and the opening angle distribution (defined in the t, t ¯ rest frames) when selection cuts are applied. Our NLOW predictions for the beam, off-diagonal, and helicity correlation for the Tevatron agree with recent measurements by the CDF and DO experiments. In addition we make predictions for estimators of these correlations as functions of M t t ¯ . These estimators may prove useful for the Tevatron and also in the early rounds of LHC data-analyses, where the event numbers will not be abundant. Furthermore, we compute to NLOW in the gauge couplings two dilepton angular correlations that are defined in the laboratory frame, for correlated and uncorrelated t t ¯ events at the LHC. Finally, based on our SM results, we identify several observables that allow to search for non-standard parity- and CP-violating interactions, especially with future LHC data.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/a27dad943339dca52204f5de212f3387d7af2e91

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Citations in the corpus

Complete off-shell effects in top quark pair hadroproduction with leptonic decay at next-to-leading order (2010, background): “Even though, the first results for next-to-leading order (NLO) QCD corrections to heavy quark production were presented more than twenty years ago [1–4], recent progress in NLO [5–9] and next-to-next-to leading order (NNLO) [10–15] calculations, as well as next-to-next-to-leading-log resummations (N”
Hadronic top-quark pair-production with one jet and parton showering (2011, background): “This issue has also been addressed in a recent paper [72], for the t̄ inclusive production, including next-to-leading order QCD and EW corrections.”
Electroweak contribution to the top quark forward-backward asymmetry at the Tevatron (2011, methodology): “We choose MRST2004QED parton distributions [23] for NLO calculations and MRST2001LO for LO [24], using thereby αs(μ) of MRST2004QED also for the evaluation of the cross sections at LO (a similar strategy was employed in [6]).”
Weak corrections to Higgs hadroproduction in association with a top-quark pair (2014, result): “The purpose of this work is to amend this situation, and to present the first calculation of such corrections; similarly to what has been done as a first step in the case of tt̄ hadroproduction [35–39], we do not include in our results effects of QED origin (dealt with in later papers [40–43] for tt”
NLO QCD corrections to off-shell top-antitop production with leptonic decays at hadron colliders (2012, methodology): “While these results agree well with theoretical calculations of other groups [30,107], the measured asymmetry is significantly higher, in particular for Mt̄t > 450GeV.”