arXiv subjects

Nikolaos Kidonakis

Publications and source records attributed to Nikolaos Kidonakis.

At least 91 records · Page 5Linked to original sources

arXiv2013

Soft-gluon resummations and NNNLO expansions

I discuss the effectiveness of soft-gluon resummations in describing higher-order corrections. I present a comparison of recent resummation approaches and their relative successes in approximating complete NNLO corrections. I also discuss fixed-order expansions through NNNLO and present some recent applications to QCD hard-scattering processes, including top-antitop pair production, single-top production, and W production at large transverse momentum.

hep-ph↗

arXiv2013

Top-quark transverse-momentum distributions in t-channel single-top production

I present approximate next-to-next-to-leading-order (NNLO) top-quark transverse momentum, pT, distributions in t-channel single-top production. These distributions are derived from next-to-next-to-leading-logarithm (NNLL) soft-gluon resummation. Theoretical results for the single top as well as the single antitop pT distributions are shown for LHC and Tevatron energies.

hep-ph↗

arXiv2013

Theoretical results for top quark production

I discuss and compare several approaches to higher-order calculations of top quark production. I study the relative effectiveness of the approaches in approximating the exact NNLO results for the top-pair total cross section and highlight the theoretical and numerical differences between them. I show that the results from my soft-gluon resummation method are nearly identical to the exact NNLO cross section at all LHC and Tevatron energies. This agreement has important consequences for the validity of existing approximate NNLO differential distributions, for further refinements of the predictions, and for applications to other processes such as single-top production. I also compare approximate NNLO top quark transverse momentum and rapidity distributions with recent LHC measurements.

hep-ph↗

arXiv2012

NNLL threshold resummation for top-pair and single-top production

I discuss threshold resummation at NNLL accuracy in the standard moment-space approach in perturbative QCD for top-pair and single-top production. For top quark pair production I present new approximate NNLO results for the total cross section and for the top quark transverse momentum and rapidity distributions at 8 TeV LHC energy. I discuss the accuracy of the soft-gluon approximation and show that the NLO and NNLO approximate results from resummation are practically indistinguishable from exact NLO and partial NNLO results. For single top production I present new approximate NNLO results for the total cross sections in all three channels at the LHC and also for the top quark transverse momentum distributions in t-channel production and in top-quark associated production with a W boson. For both ttbar and single-top production the agreement of theoretical results with LHC and Tevatron data is excellent.

hep-ph↗

arXiv2012

Single top and top pair production

I present results for single-top and top-pair production at the LHC and the Tevatron. Higher-order two-loop corrections are used to achieve NNLL resummation, which is then used to derive NNLO soft-gluon corrections. Results are presented for total cross sections, top transverse momentum distributions, and top rapidity distributions. All results are in excellent agreement with data from the LHC and the Tevatron. I also clarify the differences between various methods in top-pair production and their relation to exact NNLO results.

hep-ph↗

arXiv2012

NNLL resummation for W-boson production at large pT

We present new results for W-boson production at large transverse momentum at the LHC and the Tevatron. The contribution of soft-gluon corrections is derived from NNLL resummation and added to the exact NLO result. Numerical results and their uncertainties for the approximate NNLO W-boson transverse momentum distributions are derived and compared to recent data from the LHC.

hep-ph↗

arXiv2012

Higher-order QCD corrections for the W-boson transverse momentum distribution

We present results for W-boson production at large transverse momentum at LHC and Tevatron energies. We calculate complete next-to-leading-order (NLO) QCD corrections and higher-order soft-gluon corrections to the differential cross section. The soft-gluon contributions are resummed at next-to-next-to-leading-logarithm (NNLL) accuracy via the two-loop soft anomalous dimensions. Both NLO and approximate next-to-next-to-leading-order (NNLO) p_T distributions are presented. Our numerical results are in good agreement with recent data from the LHC.

hep-ph↗

arXiv2012

Differential and total cross sections for top pair and single top production

I present theoretical results at approximate NNLO from NNLL resummation for top quark production at the LHC and the Tevatron, including new results at 8 TeV LHC energy. Total cross sections are shown for t tbar production, for single top production in the t and s channels and via associated tW production, and for associated tH- production. Top quark transverse momentum and rapidity distributions in t tbar production are also presented, as well as new results for t-channel single top and single antitop pT distributions.

hep-ph↗

arXiv2011

Top Quark Theoretical Cross Sections and pT and Rapidity Distributions

I present theoretical results for the top quark pair total cross section, and for the top quark transverse momentum and rapidity distributions at Tevatron and LHC energies. I also present results for single top quark production in the t- and s-channels and also via associated production with a W boson. The calculations include approximate NNLO corrections that are derived from NNLL soft-gluon resummation.

hep-ph↗

arXiv2011

Two-loop corrections to W and Z boson production at high pT

We present new results for the complete two-loop corrections in the soft approximation for W and Z boson production at large transverse momentum. Analytical expressions for the NNLO approximate corrections are used to calculate transverse momentum distributions. Results for the W boson pT distribution at Tevatron and LHC energies are presented.

hep-ph↗

arXiv2011

Second-Order Approximate Corrections for QCD Processes

I present generalized formulas for approximate corrections to QCD hard-scattering cross sections through second order in the perturbative expansion. The approximate results are based on recent two-loop calculations for soft and collinear emission near threshold and are illustrated by several applications to strong-interaction processes in hadron colliders.

hep-ph↗

arXiv2011

Top-quark production and QCD

We review theoretical calculations for top-quark production that include complete next-to-leading-order QCD corrections as well as higher-order soft-gluon corrections from threshold resummation. We discuss in detail the differences between various approaches that have appeared in the literature and review results for top-quark total cross sections and differential distributions at the Tevatron and the LHC.

hep-ph↗

arXiv2011

The top quark rapidity distribution and forward-backward asymmetry

I present results for the top quark rapidity distribution at LHC and Tevatron energies, including higher-order corrections from threshold resummation. The next-to-next-to-leading-order (NNLO) soft-gluon corrections at next-to-next-to-leading-logarithm (NNLL) level are added to the NLO result. Theoretical predictions are shown for the rapidity distribution, including the scale dependence of the distributions. The forward-backward asymmetry at the Tevatron is also calculated.

hep-ph↗

arXiv2011

Renormalization group evolution of collinear and infrared divergences

I discuss collinear and infrared divergences in QCD cross sections with massless and massive final-state particles. I present the two-loop renormalization group evolution and resummation in terms of anomalous dimensions, and I show specific results for a variety of QCD hard-scattering processes.

hep-ph↗

arXiv2011

Top quark cross sections and differential distributions

I present results for the top quark pair total cross section and the top quark transverse momentum distribution at Tevatron and LHC energies. I also present results for single top quark production. All calculations include NNLO corrections from NNLL threshold resummation.

hep-ph↗

arXiv2011

Next-to-next-to-leading-order collinear and soft gluon corrections for t-channel single top quark production

I present the resummation of collinear and soft gluon corrections to single top quark production in the t channel at next-to-next-to-leading logarithm (NNLL) accuracy using two-loop soft anomalous dimensions. The expansion of the resummed cross section yields approximate next-to-next-to-leading order (NNLO) cross sections. Numerical results for t-channel single top quark (or single antitop) production at the Tevatron and the LHC are presented, including the dependence of the cross sections on the top quark mass, and the uncertainties from scale variation and parton distributions. Combined results for all single top quark production channels are also given.

hep-ph↗

arXiv2010

NNLL resummation for QCD cross sections

I present results for the resummation of soft-gluon contributions to QCD hard-scattering cross sections at next-to-next-to-leading logarithm accuracy. A key ingredient is the calculation of two-loop soft anomalous dimensions for the partonic processes. Explicit expressions and applications are provided for processes that involve massless partons and/or massive quarks.

hep-ph↗

arXiv2010

Next-to-next-to-leading soft-gluon corrections for the top quark cross section and transverse momentum distribution

I present results for top quark production in hadronic collisions at LHC and Tevatron energies. The soft-gluon corrections to the differential cross section are resummed at next-to-next-to-leading-logarithm (NNLL) accuracy via the two-loop soft anomalous dimension matrices. Approximate next-to-next-to-leading-order (NNLO) differential and total cross sections are calculated. Detailed theoretical predictions are shown for the t tbar cross section and the top quark p_T distribution at the Tevatron and the LHC.

hep-ph↗