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Atomic, Molecular and Optical Physics

Kennesaw State University

Articles 1 - 19 of 19

Full-Text Articles in Physics

Interaction Of Ultrashort-Laser Pulses With Induced Undercritical Plasmas In Fused Silica, Jeremy R. Gulley, Sebastian W. Winkler, William M. Dennis, Carl M. Liebig, Razvan Stoian Jan 2012

Interaction Of Ultrashort-Laser Pulses With Induced Undercritical Plasmas In Fused Silica, Jeremy R. Gulley, Sebastian W. Winkler, William M. Dennis, Carl M. Liebig, Razvan Stoian

Faculty and Research Publications

Ultrafast light-material interactions near the damage threshold are often studied using postmortem analysis of damaged dielectric materials. Corresponding simulations of ultrashort pulse propagation through the material are frequently used to gain additional insight into the processes leading to such damage. However, comparison between such experimental and numerical results is often qualitative, and pulses near to but not exceeding the damage threshold leave no permanent changes in the material for postmortem analysis. In this article, a series of experiments is presented that measures the near- and far-field properties of a 140-fs laser pulse after propagation through a fused silica sample in …

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Top Quark Rapidity Distribution And Forward-Backward Asymmetry, Nikolaos Kidonakis Jul 2011

Top Quark Rapidity Distribution And Forward-Backward Asymmetry, Nikolaos Kidonakis

Faculty and Research Publications

I present results for the top quark rapidity distribution at Large Hadron Collider and Tevatron energies, including higher-order corrections from threshold resummation. Approximate next-to-next-to-leading-order (NNLO) results are obtained by adding the NNLO soft-gluon corrections at next-to-next-to-leading-logarithm level to the exact next-to-leading-order calculation. 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.

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Next-To-Next-To-Leading-Order Collinear And Soft Gluon Corrections For T-Channel Single Top Quark Production, Nikolaos Kidonakis May 2011

Next-To-Next-To-Leading-Order Collinear And Soft Gluon Corrections For T-Channel Single Top Quark Production, Nikolaos Kidonakis

Faculty and Research Publications

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 accuracy using two-loop soft anomalous dimensions. The expansion of the resummed cross section yields approximate next-to-next-to-leading-order 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.

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Two-Loop Soft Anomalous Dimensions For Single Top Quark Associated Production With A W- Or H-, Nikolaos Kidonakis Sep 2010

Two-Loop Soft Anomalous Dimensions For Single Top Quark Associated Production With A W- Or H-, Nikolaos Kidonakis

Faculty and Research Publications

I present results for the two-loop soft anomalous dimensions for associated production of a single top quark with a W boson or a charged Higgs boson. The calculation uses expressions for the massive cusp anomalous dimension, which are presented in different forms, and it allows soft-gluon resummation at next-to-next-to-leading-logarithm (NNLL) accuracy. From the NNLL resummed cross section I derive approximate NNLO cross sections for bg→tW- and bg→tH- at LHC energies of 7, 10, and 14 TeV.

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Theoretical Top Quark Cross Section At The Fermilab Tevatron And The Cern Lhc, Nikolaos Kidonakis, Ramona Vogt Oct 2008

Theoretical Top Quark Cross Section At The Fermilab Tevatron And The Cern Lhc, Nikolaos Kidonakis, Ramona Vogt

Faculty and Research Publications

We present results for the top quark pair cross section at the Tevatron and the LHC. We use the resummed double differential cross section, employing the fully kinematics-dependent soft-anomalous-dimension matrices, to calculate the soft-gluon contributions at next-to-next-to-leading order (NNLO). We improve and update our previous estimates by refining our methods, including further subleading terms, and employing the most recent parton distribution function sets. The NNLO soft corrections significantly enhance the NLO cross section while considerably reducing the scale dependence. We provide a detailed discussion of all theoretical uncertainties in our calculation, including kinematics, scale, and parton distribution uncertainties, and clarify …

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Higgs Production Via B Bbar -> H In Hadron Colliders, Nikolaos Kidonakis May 2008

Higgs Production Via B Bbar -> H In Hadron Colliders, Nikolaos Kidonakis

Faculty and Research Publications

I present NNNLO collinear and soft gluon corrections for Higgs production via the process b bbar -> H. I show that the collinear corrections dominate and contribute large enhancements to the cross section at both the Tevatron and the LHC.

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Status Of Eikonal Two-Loop Calculations With Massive Quarks, Nikolaos Kidonakis, Philip Stephens May 2008

Status Of Eikonal Two-Loop Calculations With Massive Quarks, Nikolaos Kidonakis, Philip Stephens

Faculty and Research Publications

We present results for two-loop diagrams with massive quarks in the eikonal approximation. Explicit expressions are given for the UV poles in dimensional regularization of several of the required integrals.

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Higher-Order Threshold Corrections For Single Top Quark Production, Nikolaos Kidonakis Sep 2007

Higher-Order Threshold Corrections For Single Top Quark Production, Nikolaos Kidonakis

Faculty and Research Publications

I discuss single top quark production at the Tevatron and the LHC. The cross section, including soft-gluon threshold corrections through NNNLO, is presented for each partonic channel. The higher-order corrections provide significant contributions to the single top cross sections at both colliders.

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Higher-Order Soft Gluon Corrections In Single Top Quark Production At The Cern Lhc, Nikolaos Kidonakis Apr 2007

Higher-Order Soft Gluon Corrections In Single Top Quark Production At The Cern Lhc, Nikolaos Kidonakis

Faculty and Research Publications

I present a calculation of soft-gluon corrections to single top-quark production in pp collisions at the LHC via the standard model partonic processes in the t and s channels and associated top quark and W boson production. Higher-order soft-gluon corrections through next-to-next-to-next-to-leading order (NNNLO) are calculated at next-to-leading logarithmic (NLL) accuracy. The soft-gluon corrections in the s channel and in tW production are large and dominant, while in the t channel they are not a good approximation of the complete QCD corrections.

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Single Top Quark Production At The Fermilab Tevatron: Threshold Resummation And Finite-Order Soft Gluon Corrections, Nikolaos Kidonakis Dec 2006

Single Top Quark Production At The Fermilab Tevatron: Threshold Resummation And Finite-Order Soft Gluon Corrections, Nikolaos Kidonakis

Faculty and Research Publications

I present a calculation of threshold soft-gluon corrections to single top-quark production in p(p) 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 …

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Next-To-Next-To-Next-To-Leading-Order Soft-Gluon Corrections In Hard-Scattering Processes Near Threshold, Nikolaos Kidonakis Feb 2006

Next-To-Next-To-Next-To-Leading-Order Soft-Gluon Corrections In Hard-Scattering Processes Near Threshold, Nikolaos Kidonakis

Faculty and Research Publications

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-Boson Production With Large Transverse Momentum At The Lhc, Nikolaos Kidonakis, Richard J. Gonsalves, Agustin Sabio Vera Jan 2006

W-Boson Production With Large Transverse Momentum At The Lhc, Nikolaos Kidonakis, Richard J. Gonsalves, Agustin Sabio Vera

Faculty and Research Publications

We study W-boson production with large transverse momentum, QT, 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 In Hard-Scattering Processes Through Nnnlo, Nikolaos Kidonakis Jan 2006

Soft-Gluon Corrections In Hard-Scattering Processes Through Nnnlo, Nikolaos Kidonakis

Faculty and Research Publications

I discuss soft-gluon corrections in hard-scattering processes and their resummation. I present master formulas for the expansion of the resummed cross section through NNNLO and discuss the significance of these corrections in a number of processes.

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Production Of Large Transverse Momentum W Bosons At The Tevatron, Nikolaos Kidonakis, Agustin Sabio Vera Jan 2006

Production Of Large Transverse Momentum W Bosons At The Tevatron, Nikolaos Kidonakis, Agustin Sabio Vera

Faculty and Research Publications

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 …

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Soft-Gluon Expansions Through Nnnlo, Nikolaos Kidonakis Jun 2005

Soft-Gluon Expansions Through Nnnlo, Nikolaos Kidonakis

Faculty and Research Publications

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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Collinear And Soft Resummation In The Large-X Limit, Nikolaos Kidonakis Jun 2005

Collinear And Soft Resummation In The Large-X Limit, Nikolaos Kidonakis

Faculty and Research Publications

I discuss general unified formulas for resumming collinear and soft contributions to QCD hard scattering cross sections at laxge 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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Top Quark And Charged Higgs Production At Hadron Colliders, Nikolaos Kidonakis May 2005

Top Quark And Charged Higgs Production At Hadron Colliders, Nikolaos Kidonakis

Faculty and Research Publications

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, Nikolaos Kidonakis May 2005

Charged Higgs Production Via Bg -> Th(-) At The Lhc, Nikolaos Kidonakis

Faculty and Research Publications

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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Charged Higgs Production: Higher-Order Corrections, Nikolaos Kidonakis Jan 2005

Charged Higgs Production: Higher-Order Corrections, Nikolaos Kidonakis

Faculty and Research Publications

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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