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The virtuality-dependent beam function is a universal ingredient in the resummation for observables probing the virtuality of incoming partons, including N-jettiness and beam thrust. We compute the gluon beam function at two-loop order.…

High Energy Physics - Phenomenology · Physics 2015-06-19 Jonathan Gaunt , Maximilian Stahlhofen , Frank J. Tackmann

In this talk we discuss recent progress concerning precise predictions for the LHC. We give a status report of an application of the GOLEM method to deal with multi-leg one-loop amplitudes, namely the next-to-leading order QCD corrections…

High Energy Physics - Phenomenology · Physics 2008-07-07 S. Karg , G. Sanguinetti

Chiral amplitudes for two jets processes in quasi-peripheral kinematics are calculated at the Born and one loop correction level. The amplitudes of subprocesses describing interaction of virtual and real photon with creation of a charged…

High Energy Physics - Phenomenology · Physics 2016-09-06 V. Bytev , E. Bartos , M. V. Galynskii , E. A. Kuraev

Gluon fusion processes like single and double Higgs production exhibit slow convergence and pose severe computational challenges. We show how the top-quark mass dependence of the virtual amplitudes can be reconstructed with a conformal…

High Energy Physics - Phenomenology · Physics 2020-08-27 Joshua Davies , Ramona Gröber , Andreas Maier , Thomas Rauh , Matthias Steinhauser

After a brief general introduction about the integrand-reduction method, we will review the main features of the GoSam 2.0 automated framework for one-loop calculations and illustrate its application to SM processes involving the production…

High Energy Physics - Phenomenology · Physics 2016-01-19 Giovanni Ossola

We describe a new method for the automated construction of one-loop amplitudes based on the open-loop algorithm, where various operations are performed on-the-fly while constructing the integrand. In particular, an on-the-fly reduction…

High Energy Physics - Phenomenology · Physics 2018-01-12 Federico Buccioni , Stefano Pozzorini , Max Zoller

In this paper, we show how to calculate analytically the one-loop helicity amplitudes for the process $q\bar{q} rightarrow t\bar{t}$ induced by KK gluon, using the spinor-helicity formalism. A minimal set of Feynman rules which are uniquely…

High Energy Physics - Phenomenology · Physics 2011-09-15 Hua Xing Zhu , Chong Sheng Li , Liang Dai , Jun Gao , Jian Wang , C. -P. Yuan

We compute next-to-leading order virtual two-loop corrections to the process $gg\to ZZ$ in the low- and high-energy limits, considering the contributions with virtual top quarks. Analytic results for all 20 form factors are presented…

High Energy Physics - Phenomenology · Physics 2020-02-14 Joshua Davies , Go Mishima , Matthias Steinhauser , David Wellmann

We present results for the O(alpha_s) virtual corrections to q g -> W b bbar q' obtained with a new automatized approach to the evaluation of one-loop amplitudes in terms of Feynman diagrams. Together with the O(alpha_s) corrections to q q'…

High Energy Physics - Phenomenology · Physics 2015-05-30 Laura Reina , Thomas Schutzmeier

We calculate next-to-leading-order (NLO) corrections to exclusive processes in $k_T$ factorization theorem, taking $\pi\gamma^*\to\gamma$ as an example. Partons off-shell by $k_T^2$ are considered in both the quark diagrams from full QCD…

High Energy Physics - Phenomenology · Physics 2008-11-26 Soumitra Nandi , Hsiang-nan Li

We present an update on the next-to-leading order calculation of the rate for Higgs boson production in association with two jets. Our new calculation incorporates the full analytic result for the one-loop virtual amplitude. Results are…

High Energy Physics - Phenomenology · Physics 2010-05-21 John M. Campbell , R. Keith Ellis , Ciaran Williams

Jets provide one of the primary probes of the quark-gluon plasma produced in ultrarelativistic heavy ion collisions and the cold nuclear matter explored in deep inelastic scattering experiments. However, despite important developments in…

High Energy Physics - Phenomenology · Physics 2024-01-10 João Barata , Xiaojian Du , Meijian Li , Wenyang Qian , Carlos A. Salgado

In this talk we present techniques for calculating one-loop amplitudes for multi-leg processes using Feynman diagrammatic methods in a semi-algebraic context. Our approach combines the advantages of the different methods allowing for a fast…

We investigate the next-to-leading logarithmic (NLL) order contributions of the quantum chromodynamics (QCD) for exclusive processes evaluated by Monte Carlo methods. Ambiguities of the Monte Carlo calculation based on the…

High Energy Physics - Phenomenology · Physics 2011-12-06 Hidekazu Tanaka

At very high energies, in the infinite momentum frame and in light cone gauge, a hard scale proportional to the high parton density arises in QCD. In an effective theory of QCD at small $x$, this scale is of order $\alpha_S\mu$, where $\mu$…

High Energy Physics - Phenomenology · Physics 2009-10-31 Alex Krasnitz , Raju Venugopalan

We present results for the production of a pair of on-shell Z bosons via gluon fusion. This process occurs both through the production and decay of the Higgs boson, and through continuum production where the Z boson couples to a loop of…

High Energy Physics - Phenomenology · Physics 2016-08-09 John M. Campbell , R. Keith Ellis , Michal Czakon , Sebastian Kirchner

One-loop counterterms are computed in the first order formalism for the Einstein-Hilbert action with a minimally coupled scalar field using the background field method and the heat kernel technique. The {\em off-shell} divergent piece in…

High Energy Physics - Theory · Physics 2021-09-14 Enrique Alvarez , Jesus Anero , Raquel Santos-Garcia

The interpretation of virtual gluons as ghosts in the non-linear gluonic structure of QCD permits the formulation and realization of a manifestly gauge-invariant and Lorentz covariant theory of interacting quarks/anti-quarks, for all values…

High Energy Physics - Theory · Physics 2010-02-11 H. M. Fried , Y. Gabellini , T. Grandou , Y. -M. Sheu

This report describes the recent efforts to compute analytic formulae for the Next-to-Leading-Order (NLO) QCD corrections to Higgs plus two jet production at hadron colliders. In these calculations the Higgs boson couples to gluons via a…

High Energy Physics - Phenomenology · Physics 2014-11-20 Ciaran Williams

We examine properties of small-radius jets, focusing on phenomenological applications to the inclusive jet spectrum. We match fixed-order calculations with the leading-logarithmic resummation of the jet radius (LL$_R$), and propose a new…

High Energy Physics - Phenomenology · Physics 2016-06-13 Frédéric A. Dreyer