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We calculate the complete electroweak O(alpha) corrections to pp, pbar p -> l+l- X (l=e, mu) in the Standard Model of electroweak interactions. They comprise weak and photonic virtual one-loop corrections as well as real photon radiation to…

High Energy Physics - Phenomenology · Physics 2010-04-06 U. Baur , O. Brein , W. Hollik , C. Schappacher , D. Wackeroth

We present the NNLO QCD virtual corrections for qurak-antiquark -> gluon photon, quark-antiquark -> photon photon and the NNLO QED virtual corrections for electron positron -> photon photon and all processes related by crossing symmetry. We…

High Energy Physics - Phenomenology · Physics 2008-11-26 C. Anastasiou , E. W. N. Glover , M. E. Tejeda-Yeomans

We compute the two-loop corrections to the helicity amplitudes for the coupling of a massive vector boson to a massless quark-antiquark pair and a gluon, accounting for vector and axial-vector couplings of the vector boson and…

High Energy Physics - Phenomenology · Physics 2023-06-19 Thomas Gehrmann , Tiziano Peraro , Lorenzo Tancredi

We outline the computational details to obtain mixed EW-QCD corrections to on-shell production of a single vector boson at the LHC at two-loop level. We use the method of differential equation to obtain the pure virtual, real-virtual and…

High Energy Physics - Phenomenology · Physics 2019-12-24 Roberto Bonciani , Federico Buccioni , Narayan Rana , Alessandro Vicini

For the first time full next-to-leading-order electroweak corrections to off-shell vector-boson scattering are presented. The computation features the complete matrix elements, including all non-resonant and off-shell contributions, to the…

High Energy Physics - Phenomenology · Physics 2017-07-05 Benedikt Biedermann , Ansgar Denner , Mathieu Pellen

This paper is devoted to the two-loop QED radiative corrections to the decay pi0 -> e+ e-. We compute the virtual corrections without using any approximation and we take into account all the relevant graphs with the inclusion of those…

High Energy Physics - Phenomenology · Physics 2011-11-09 Petr Vaško , Jiří Novotný

We present a semi-numerical algorithm to calculate one-loop virtual corrections to scattering amplitudes. The divergences of the loop amplitudes are regulated using dimensional regularization. We treat in detail the case of amplitudes with…

High Energy Physics - Phenomenology · Physics 2008-11-26 R. K. Ellis , W. T. Giele , G. Zanderighi

In this thesis, we study the three-loop QCD form factors. After an introduction and a discussion of the physics motivation, we generate the quark form factor using Qgraf. We then show how to bring the Feynman integrals into a unique form by…

High Energy Physics - Phenomenology · Physics 2009-03-04 Beat Toedtli

We use functional methods to compute one-loop effects in Heavy Quark Effective Theory. The covariant derivative expansion technique facilitates the efficient extraction of matching coefficients and renormalization group evolution equations.…

High Energy Physics - Phenomenology · Physics 2020-07-15 Timothy Cohen , Marat Freytsis , Xiaochuan Lu

Using the asymptotic-expansion technique, we compute the dominant two-loop electroweak corrections, of O(G_F m_t^2), to production and decay via a pair of photons or gluons of the CP-odd Higgs boson A^0 in a two-Higgs-doublet model with…

High Energy Physics - Phenomenology · Physics 2008-11-26 Joachim Brod , Frank Fugel , Bernd A. Kniehl

Recently exact results for the complete electroweak two-loop contributions to the effective weak mixing angle were published. This paper illustrates the techniques used for this computation, in particular the methods for evaluating the loop…

High Energy Physics - Phenomenology · Physics 2009-11-11 M. Awramik , M. Czakon , A. Freitas

We review recent theoretical progress in the computation of radiative corrections beyond one loop within the standard model of electroweak interactions, both in the gauge and Higgs sectors. In the gauge sector, we discuss universal…

High Energy Physics - Phenomenology · Physics 2015-06-25 Bernd A. Kniehl

We compute two-loop electroweak corrections to Higgs boson pair and Higgs plus jet production, taking into account all sectors of the Standard Model. All diagrams with virtual top quarks are computed in an expansion for large top quark mass…

High Energy Physics - Phenomenology · Physics 2023-10-10 Joshua Davies , Kay Schönwald , Matthias Steinhauser , Hantian Zhang

With the increasing experimental precision available at colliders, higher-order perturbative calculations are required to reduce the theory uncertainty in order to extract crucial QCD parameters, such as the strong coupling constant, to the…

High Energy Physics - Phenomenology · Physics 2022-08-15 Marco Saragnese

We construct a specific formalism for calculating the one-loop virtual corrections for standard model processes with an arbitrary number of external legs. The procedure explicitly separates the infrared and ultraviolet divergences…

High Energy Physics - Phenomenology · Physics 2009-11-10 W. T. Giele , E. W. N. Glover

We examine the role of O(\alpha_s) perturbative corrections to the pion elastic form factor F_\pi(Q^2). We express the quark current three-point function in terms of light cone variables and use Borel transformation to simultaneously model…

High Energy Physics - Phenomenology · Physics 2014-11-17 Adam Szczepaniak , Anatoly Radyushkin , Chueng-Ryong Ji

Two-loop contributions to the electromagnetic form factors are calculated in the kinematic regime close to the fermion-antifermion threshold. The results are presented in an expansion in the velocity $\beta$ of the fermions in the c.m.…

High Energy Physics - Phenomenology · Physics 2014-11-17 A. H. Hoang

We present in detail the calculation of the virtual O(alpha_s) corrections to the inclusive semi-leptonic rare decay b --> s l+ l-. We also include those O(alpha_s) bremsstrahlung contributions which cancel the infrared and mass…

High Energy Physics - Phenomenology · Physics 2014-11-17 H. H. Asatryan , H. M. Asatrian , C. Greub , M. Walker

We compute the three-loop corrections to the potential of two heavy quarks. In particular we consider in this Letter the purely gluonic contribution which provides in combination with the fermion corrections of Ref. \cite{Smirnov:2008pn}…

High Energy Physics - Phenomenology · Physics 2010-04-23 Alexander V. Smirnov , Vladimir A. Smirnov , Matthias Steinhauser

We calculate analytically the two-loop triangle integrals entering the $\mathcal{O}(\alpha\alpha_s)$ corrections to the $HZV$ vertex with $V=Z^*,\gamma^*$ using the method of differential equations. Our result provides a prototype to study…

High Energy Physics - Phenomenology · Physics 2019-10-23 Yuxuan Wang , Xiaofeng Xu , Li Lin Yang