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Nikolaos Kidonakis

Publications and source records attributed to Nikolaos Kidonakis.

At least 127 records · Page 7Linked to original sources

Single top quark production at the Tevatron: threshold resummation and finite-order soft gluon corrections

I present a calculation of threshold soft-gluon corrections to single top quark production in ppbar collisions via all partonic processes in the t and s channels and via associated top quark and W boson production. The soft-gluon corrections are formally resummed to all orders, and finite-order expansions of the resummed cross section are calculated through next-to-next-to-next-to-leading order (NNNLO) at next-to-leading logarithmic (NLL) accuracy. Numerical results for single top quark production at the Tevatron are presented, including the dependence of the cross sections on the top quark mass and on the factorization and renormalization scales. The threshold corrections in the t channel are small while in the s channel they are large and dominant. Associated tW production remains relatively minor due to the small leading-order cross section even though the K factors are large.

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W-boson production with large transverse momentum at the LHC

We study W-boson production with large transverse momentum, Q_T, in pp collisions at the LHC. We calculate the complete NLO corrections and the soft-gluon NNLO corrections to the differential cross section. The NLO corrections are large but they do not reduce the scale dependence relative to LO, while the NNLO soft-gluon corrections, although small, significantly reduce the scale dependence and thus provide a more stable result.

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Soft-gluon corrections to hard-scattering cross sections through NNNLO

I present a systematic approach to calculating soft-gluon corrections through next-to-next-to-next-to-leading order for arbitrary hard-scattering cross sections. Using a unified approach, master formulas are derived for processes with both simple and complex color flows. Applications and numerical results are given for some processes of interest, including charged Higgs production and top quark production in the Standard Model and beyond.

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Charged Higgs production: higher-order corrections

I present a calculation of higher-order radiative corrections to charged Higgs production in association with a top quark via the process bg -> tH-. Results for charged Higgs production at the LHC are presented, including the dependence of the cross section on the charged Higgs mass, the top quark mass, the factorization and renormalization scales, and tan beta. I show that the theoretical prediction for the cross section is significantly enhanced and is greatly stabilized when the higher-order corrections are included.

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Next-to-next-to-next-to-leading-order soft-gluon corrections in hard-scattering processes near threshold

I present a unified calculation of soft-gluon corrections to hard-scattering cross sections through next-to-next-to-next-to-leading order (NNNLO). Master formulas are derived, from a threshold resummation formalism, that can be applied to total and differential cross sections for hard-scattering processes in hadron colliders. I also present numerical results for charged Higgs production at the LHC where these corrections are large, and for top quark production at the Tevatron where these corrections greatly reduce the scale dependence of the cross section.

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W production at large transverse momentum at the Large Hadron Collider

We study the production of W bosons at large transverse momentum in pp collisions at the Large Hadron Collider (LHC). We calculate the complete next-to-leading order (NLO) corrections to the differential cross section. We find that the NLO corrections provide a large increase to the cross section but, surprisingly, do not reduce the scale dependence relative to leading order (LO). We also calculate next-to-next-to-leading-order (NNLO) soft-gluon corrections and find that, although they are small, they significantly reduce the scale dependence thus providing a more stable theoretical prediction.

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Soft-gluon expansions through NNNLO

I present universal master formulas for soft-gluon corrections to hard-scattering cross sections through next-to-next-to-next-to-leading order (NNNLO). I also briefly discuss applications to some processes where these corrections enhance the cross section and decrease the scale dependence.

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Top quark and charged Higgs production at hadron colliders

I present a brief theoretical update on top quark pair production at the Tevatron and give values of the NNLO-NNNLL cross section for both m_t=175 and 178 GeV. I then present a calculation of the cross section for charged Higgs production in association with a top quark at the LHC, including NNLO soft-gluon corrections.

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Charged Higgs production via bg -> tH- at the LHC

I present a calculation of QCD radiative corrections to charged Higgs production via the process bg -> tH-. I show that the cross section is dominated by soft-gluon corrections, which are computed through next-to-next-to-leading order. Results for charged Higgs production at the LHC are presented, including the dependence of the cross section on the charged Higgs mass, the top quark mass, the factorization and renormalization scales, and tan beta.

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Theoretical status of the top quark cross section

We discuss the most recent calculations of the top quark total cross section and transverse momentum distributions at the Tevatron and the LHC. These calculations include the soft-gluon corrections at next-to-next-to-leading order (NNLO). The soft NNLO corrections stabilize the scale dependence of the cross section.

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Collinear and soft resummation in the large-x limit

I discuss general unified formulas for resumming collinear and soft contributions to QCD hard scattering cross sections at large x. Expansions of the resummed cross sections to next-to-next-to-next-to-leading order are also shown along with applications of the formalism.

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Production of Large Transverse Momentum W Bosons at the Tevatron

We discuss the production of W bosons at large transverse momentum in p pbar collisions at the Tevatron Run I and II. W boson hadroproduction is a process of relevance in testing the Standard Model and in estimates of backgrounds to new physics. The next-to-leading order cross section in the region of large transverse momentum is dominated by threshold soft-gluon corrections which arise from incomplete cancellations near partonic threshold between graphs with real emission and virtual graphs due to the limited phase space available for real gluon emission. In this contribution it is shown how, by including next-to-next-to-leading-order (NNLO) soft-gluon corrections, the transverse momentum distribution of the W at the Tevatron is modestly enhanced and the dependence on the factorization and renormalization scales is significantly reduced.

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Large-Q_T W-boson production at the Tevatron

The production of W bosons at large transverse momentum at the Tevatron is dominated by soft-gluon corrections. In this talk we present a calculation of these corrections at next-to-next-to-leading order. The corrections enhance the transverse momentum distribution of the W while reducing the scale dependence.

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Anomalous tqV couplings and FCNC top quark production

We discuss FCNC top quark production via anomalous tqV couplings at the Tevatron and HERA colliders. We calculate higher-order soft-gluon corrections to such processes and demonstrate the stabilization of the cross section when these corrections are included.

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Charged Higgs production with a top quark at the LHC

I discuss charged Higgs production via the process bg -> t H- at the LHC. I show that the cross section is dominated by soft-gluon corrections and I provide results for its dependence on the charged Higgs mass and on the scale, including higher-order effects.

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W Boson Production at Large Transverse Momentum

The production of W bosons at large transverse momentum in p pbar collisions is studied. The next-to-leading order cross section in this region is dominated by threshold soft-gluon corrections. The transverse momentum distribution of the W at the Tevatron is modestly enhanced when next-to-next-to-leading-order soft-gluon corrections are added, and the dependence on the factorization and renormalization scales is significantly reduced.

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