Top-quark pair hadroproduction at NNLO: differential predictions with the $$ \overline{\mathrm{MS}} $$ mass

Abstract

We consider top-quark pair production at the LHC within the MS scheme for the renormalisation of the top-quark mass, and we present predictions for total and differential cross sections at next-to-next-to-leading order (NNLO) in QCD. Our state-ofthe-art calculation extends the available differential results by one order in the perturbative expansion, and it is relevant for a precise determination of the top-quark mass, including possible effects of the running mass in the MS scheme. We consider variations of the scale at which the MS mass of the top quark is evaluated, extending the usual 7-point to a 15-point scale variation. This additional variation is crucial for a reliable estimate of the theoretical uncertainties, especially at low perturbative orders and close to the production threshold of the top-quark pair. We also compute, for the first time, the invariant-mass distribution of the top-quark pair by using a running mass, evaluated at a dynamic scale. Our predictions for the invariant-mass distribution in the MS scheme are compared with a recent measurement performed by the CMS Collaboration. We observe that the inclusion of the NNLO corrections improves the agreement with the data, and we discuss effects due to the QCD running of the MS mass of the top quark.

Multiloop contributions to the on-shell-$$ \overline{{\mathrm{MS}}}$$ heavy quark mass relation in QCD and the asymptotic structure of the corresponding series: the updated consideration

“…Indeed, the contributions of the seventh, eighth and ninth orders are comparable to each other. Further, using the higher-order t-quark estimates for the coefficients t M k , obtained in [50] with help of the IRR-based formula (33), we conclude that in this case the numerical contributions to the relation between M t and m t (m 2 t ) are close to the FLones presented in (40). Therefore, the statement about the manifestation of the asymptotic behavior of the PT series for the ratio M t /m t (m 2 t ) after the seventh order seems to us quite reliable.…”

“…This problem is still under careful examinations (see [37,38] and the reviews of [33,34]). The arising inaccuracies should be compared with other theoretical errors, which enter into the determinations of both running and pole top-quark masses [24,39,40]. Moreover, the uncertainties, contributed by at least the first not yet computed highorder correction to the relation between the pole and running masses, are also of interest [38,41].…”

Heavy-flavor hadro-production with heavy-quark masses renormalized in the $$ \overline{\mathrm{MS}} $$, MSR and on-shell schemes

“…[38] and the total cross-sections in table 1 of ref. [42]). In case of charm a reduction of scale uncertainties when using dynamical µ m instead of static µ m is not visible in any of the scale variation configurations.…”

“…Various phenomenological and experimental investigations on top quark hadro-production with top mass renormalized in the MS scheme already exist in the literature (see e.g. [36][37][38][39][40][41][42]). On the other hand, the MSR mass is discussed in various theory papers, mainly focusing on its definition and properties (see e.g.…”

PineAPPL: combining EW and QCD corrections for fast evaluation of LHC processes

“…This fact suggests that, once included in a global fit, EW corrections can improve the accuracy of the PDFs. In comparison to the scale uncertainty, the size of the EW corrections remains negligible: despite the fact that the choice of factorisation and renormalisation scales have been devised to optimise the convergence of the perturbative expansion, NNLO QCD corrections remain large [103][104][105][106][107][108][109][110][111], as expected in a process mostly initiated by gluons. Their inclusion is therefore mandatory in a fit of PDFs.…”