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

By Valentin Ahrens, A. Ferroglia, M. Neubert, B. Pecjak, Li Lin Yang. 2010

236 citations recorded by the source corpus.

Precision predictions for phenomenologically interesting observables such as the $ t\bar{t} $ invariant mass distribution and forward-backward asymmetry in top-quark pair production at hadron colliders require control over the differential cross section in perturbative QCD. In this paper we improve existing calculations of the doubly differential cross section in the invariant mass and scattering angle by using techniques from soft-collinear effective theory to perform an NNLL resummation of threshold logarithms, which become large when the invariant mass M of the top-quark pair approaches the partonic center-of-mass energy $ \sqrt {{\hat{s}}} $. We also derive an approximate formula for the differential cross section at NNLO in fixed-order perturbation theory, which completely determines the coefficients multiplying the singular plus distributions in the variable $ \left( {1 - {{{{M^2}}} \left/ {{\hat{s}}} \right.}} \right) $. We then match our results in the threshold region with the exact results at NLO in fixed-order perturbation theory, and perform a numerical analysis of the invariant mass distribution, the total cross section, and the forward-backward asymmetry. We argue that these are the most accurate predictions available for these observables at present. Using MSTW2008NNLO parton distribution functions (PDFs) along with αs(MZ) = 0.117 and mt = 173.1 GeV, we obtain for the inclusive production cross sections at the Tevatron and LHC the values $ {{{\sigma }}_{\text{Tevatron}}} = \left( {6.30\pm 0.19_{ - 0.23}^{ + 0.31}} \right){\text{pb}} $ and σLHC = (149 ± 7 ± 8) pb, where the first error results from scale variations while the second reflects PDF uncertainties.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/edbd37445ba7544718723e5fc51f9307be10f8a5

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Citations in the corpus

NNLL resummation for squark-antisquark pair production at the LHC (2011, unknown): “Studies for the pair production of top quarks suggest that the effect of the matching coefficients can be significant [36] and that NNLL resummation can reduce the scale dependence considerably [35,37–40].”
Introduction to Soft-Collinear Effective Theory (2014, methodology): “These are the production threshold limit ŝ → 4m(2)t [185–187], which is employed in order to calculate the total top-quark pair-production cross section, the soft emission limit in Pair Invariant Mass kinematics (PIM), needed for the calculation of the pair invariant-mass distribution [44,45], and t”
Dynamical scales for multi-TeV top-pair production at the LHC (2016, methodology): “Such scales have been used in the past [38, 39] as well as recently in the resummation-based work [40, 41].”
NLO QCD corrections to off-shell top-antitop production with leptonic decays at hadron colliders (2012, methodology): “Later also electroweak radiative corrections were calculated [5–10], and recently important progress has been achieved both in the resummation of logarithmically enhanced terms [11–14] and towards the inclusion of QCD corrections at next-to-next-to-leading-order (NNLO) [15–25].”
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”
Soft gluon resummation for gluon-induced Higgs Strahlung (2014, background): “The difference between the two approaches has been studied in the literature in the context of tt̄ production [39, 54, 55].”