Renormalization-group improved predictions for top-quark pair production at hadron colliders

139

156

We calculate all major differential distributions with stable top-quarks at the LHC. The calculation covers the multi-TeV range that will be explored during LHC Run II and beyond. Our results are in the form of high-quality binned distributions. We offer predictions based on three different parton distribution function (pdf) sets. In the near future we will make our results available also in the more flexible fastNLO format that allows fast re-computation with any other pdf set. In order to be able to extend our calculation into the multi-TeV range we have had to derive a set of dynamic scales. Such scales are selected based on the principle of fastest perturbative convergence applied to the differential and inclusive cross-section. Many observations from our study are likely to be applicable and useful to other precision processes at the LHC. With scale uncertainty now under good control, pdfs arise as the leading source of uncertainty for TeV top production. Based on our findings, true precision in the boosted regime will likely only be possible after new and improved pdf sets appear. We expect that LHC top-quark data will play an important role in this process.

Section: Jhep04(2017)071supporting

confidence: 68%

“…(3.4) below. Scales based on m T (3.2) have been used since the early days of NLO calculations [30,31,36,37], as well as, more recently, m tt -based scales [38][39][40][41].…”

Section: Jhep04(2017)071mentioning

confidence: 99%

Dynamical scales for multi-TeV top-pair production at the LHC

Czakon

Heymes

Mitov

2017

139

156

“…[117] shown in figure 5 is adapted from figure 9 in ref. [5]: the results from [117] are NLO+NNLL (next-to-next-to-leading log); resummation is performed in momentum space with a default scale choice µ = m tt ; however, unlike figure 9 in [5], they are shown here with their normalisation not rescaled to exact NNLO. In figure 5 we notice that the approximate NNLO result of ref.…”

Section: Comparison With Approximate Nnlo/resummed Nlo Qcd Resultsmentioning

confidence: 99%

NNLO QCD predictions for fully-differential top-quark pair production at the Tevatron

Czakon

Fiedler

Heymes

et al. 2016

125

We present a comprehensive study of differential distributions for Tevatron top-pair events at the level of stable top quarks. All calculations are performed in NNLO QCD with the help of a fully differential partonic Monte-Carlo and are exact at this order in perturbation theory. We present predictions for all kinematic distributions for which data exists. Particular attention is paid on the top-quark forward-backward asymmetry which we study in detail. We compare the NNLO results with existing approximate NNLO predictions as well as differential distributions computed with different parton distribution sets. Theory errors are significantly smaller than current experimental ones with overall agreement between theory and data.

“…• Differential tt cross section as a function of M tt from CDF [24] (table 3, all bins but the first), to be compared with the approximate NNLO calculation of [25] (figure 12).…”

Section: Global Fit To the Top Tevatron Datamentioning

confidence: 99%

Predictions from heavy new physics interpretation of the top forward-backward asymmetry

Delaunay

Gedalia

Hochberg

et al. 2012

We derive generic predictions at hadron colliders from the large forwardbackward asymmetry observed at the Tevatron, assuming the latter arises from heavy new physics beyond the Standard Model. We use an effective field theory approach to characterize the associated unknown dynamics. By fitting the Tevatron tt data we derive constraints on the form of the new physics. Furthermore, we show that heavy new physics explaining the Tevatron data generically enhances at high invariant masses both the top pair production cross section and the charge asymmetry at the LHC. This enhancement can be within the sensitivity of the 8 TeV run, such that the 2012 LHC data should be able to exclude a large class of models of heavy new physics or provide hints for its presence. The same new physics implies a contribution to the forward-backward asymmetry in bottom pair production at low invariant masses of order a permil at most.