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Full-Text Articles in Physics
Top Quark Production, Nikolaos Kidonakis
Top Quark Production, Nikolaos Kidonakis
Faculty and Research Publications
I discuss top quark production in hadronic collisions. I present the soft-gluon resummation formalism and its derivation from factorization and renormalization-group evolution, and two-loop calculations of soft anomalous dimensions in the eikonal approximation. I discuss the contributions of next-to-next-to-leading order (NNLO) soft-gluon corrections to the total cross sections and top-quark transverse momentum and rapidity distributions for top-antitop pair production, and for single-top production in the t and s channels and in association with a W boson or a charged Higgs boson.
Top Quark Working Group Report, Nikolaos Kidonakis, Et. Al.
Top Quark Working Group Report, Nikolaos Kidonakis, Et. Al.
Faculty and Research Publications
The top quark was discovered in 1995 [1, 2] and it is still the heaviest elementary particle known today. Thanks to its large mass, and the related strength of its coupling to the Higgs boson, the top quark may be a key player in understanding the details of electroweak symmetry breaking. Studies of the top quark properties at the Tevatron and Run I of the LHC have given us a detailed understanding of many properties of this particle, including its mass, production and decay mechanisms, electric charge and more. With the exception of the large forward-backward asymmetry in tt¯ production …
Fcnc Top Quark Production Via Anomalous Couplings, Nikolaos Kidonakis, Elwin Martin
Fcnc Top Quark Production Via Anomalous Couplings, Nikolaos Kidonakis, Elwin Martin
Faculty and Research Publications
We calculate flavor-changing neutral current (FCNC) processes with top-quark production via anomalous couplings at LHC energies. We report on progress on the FCNC processes gu -> tZ, gu -> t gamma and gu -> tg. We go beyond leading order and include soft-gluon corrections through next-to-next-to-leading order.
Soft-Gluon Resummations And Nnnlo Expansions, Nikolaos Kidonakis
Soft-Gluon Resummations And Nnnlo Expansions, Nikolaos Kidonakis
Faculty and Research Publications
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.
Studies Of Highly-Boosted Top Quarks Near The Tev Scale Using Jet Masses At The Lhc, B. Auerbach, S. V. Chekanov, Nikolaos Kidonakis
Studies Of Highly-Boosted Top Quarks Near The Tev Scale Using Jet Masses At The Lhc, B. Auerbach, S. V. Chekanov, Nikolaos Kidonakis
Faculty and Research Publications
Studies of highly-boosted top quarks produced inclusively in pp collisions at √ s = 14 TeV are discussed. Using Monte Carlo models after a fast detector simulation, it is shown that jet masses alone provide a sensitive probe for top quarks produced inside highp T jets. The hadronic decays of such top quarks can be studied in a data-driven approach by analysing shapes of jet-mass distributions. It is shown that inclusive production of boosted top quarks can be observed if it has a cross section at least twice larger than the prediction from the approximate next-to-next-to-leading-order (aNNLO) calculation for the …
Top-Quark Transverse-Momentum Distributions In T-Channel Single-Top Production, Nikolaos Kidonakis
Top-Quark Transverse-Momentum Distributions In T-Channel Single-Top Production, Nikolaos Kidonakis
Faculty and Research Publications
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.
Top Quark Transverse Momentum And Rapidity Distributions, Nikolaos Kidonakis
Top Quark Transverse Momentum And Rapidity Distributions, Nikolaos Kidonakis
Faculty and Research Publications
I present NNLO approximate calculations, based on NNLL resummation, for top quark differential transverse momentum and rapidity distributions. In particular recent results are presented for top-pair production and single-top production processes and compared to the latest experimental data from the LHC.
The Jet-Disk Connection: Evidence For A Reinterpretation In Radio-Loud And Radio-Quiet Active Galactic Nuclei, David Garofalo
The Jet-Disk Connection: Evidence For A Reinterpretation In Radio-Loud And Radio-Quiet Active Galactic Nuclei, David Garofalo
Faculty and Research Publications
To constrain models of the jet-disc connection, we explore Eddington ratios reported in Foschini (2011) and interpret them in relation to the values in Sikora et al. across the active galactic nuclei population from radio loud quasars, their flat spectrum radio quasar subclass, the recently discovered gamma-ray loud narrow-line type 1 Seyfert galaxies, Fanaroff-Riley type I (FRI) radio galaxies and radio quiet quasars of the Palomar Green survey. While appeal to disc truncation in radiatively inefficient flow appears to explain the observed inverse relation between radio loudness and Eddington ratio in radio loud and radio quiet quasars, FR I objects, …
Theoretical Results For Top Quark Production, Nikolaos Kidonakis
Theoretical Results For Top Quark Production, Nikolaos Kidonakis
Faculty and Research Publications
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 …
Retrograde Versus Prograde Models Of Accreting Black Holes, David Garofalo
Retrograde Versus Prograde Models Of Accreting Black Holes, David Garofalo
Faculty and Research Publications
There is a general consensus that magnetic fields, accretion disks, and rotating black holes are instrumental in the generation of the most powerful sources of energy in the known universe. Nonetheless, because magnetized accretion onto rotating black holes involves both the complications of nonlinear magnetohydrodynamics that currently cannot fully be treated numerically, and uncertainties about the origin of magnetic fields that at present are part of the input, the space of possible solutions remains less constrained. Consequently, the literature still bears witness to the proliferation of rather different black hole engine models. But the accumulated wealth of observational data is …
Higher-Order Qcd Corrections For The W-Boson Transverse Momentum Distribution, Nikolaos Kidonakis, Richard J. Gonsalves
Higher-Order Qcd Corrections For The W-Boson Transverse Momentum Distribution, Nikolaos Kidonakis, Richard J. Gonsalves
Faculty and Research Publications
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-toleading-order (NNLO) pT distributions are presented. Our numerical results are in good agreement with recent data from the LHC.