Abstract
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.
Highlights
In this paper we take the first step towards the systematic study of theoretical uncertainties in precision fully-differential top-pair production at the LHC with stable top quarks
The results derived here make it possible to describe stable top quark production into the multi-TeV regime which will be explored in detail during LHC Run II
The relatively small bin sizes for our results, coupled with their small Monte Carlo errors, would allow one to produce high-quality analytic fits to all distributions. We expect that such fits could subsequently be used for further rebinning to a different bin size, at the expense of tolerable errors. This way our results could be extended to accommodate diverse bin configurations; in order to allow for a change of parton distribution sets we will release in the near future our results as fastNLO library tables
Summary
To summarise our discussion of scale-setting for the total cross-section in figure 4 we compare all scales used so far in NNLO QCD (and NNLO+NNLL where available) and for both pdf sets From this figure it is easy to see that at this order of perturbation theory the predictions are rather stable with respect to the choice of pdf set (at least for the pdf sets we have studied) and that the choice of a scale ensuring fastest convergence is a rather clear cut. Such scale returns value for σtot which is in nearly perfect agreement with the so-far default value for σtot evaluated with NNLO+NNLL at the scale μ = mt.
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