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Related papers: Two-loop QED Operator Matrix Elements with Massive…

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We describe the calculation of the two--loop massive operator matrix elements with massive external fermions in QED. We investigate the factorization of the $O(\alpha^2)$ initial state corrections to $e^+e^-$ annihilation into a virtual…

High Energy Physics - Phenomenology · Physics 2011-11-29 J. Blümlein , A. De Freitas , W. L. van Neerven

We describe the calculation of the two--loop massive operator matrix elements for massive external fermions. These matrix elements are needed for the calculation of the $O(\alpha^2)$ initial state radiative corrections to $e^+e^-$…

High Energy Physics - Phenomenology · Physics 2009-04-14 J. Blümlein , A. De Freitas , W. van Neerven

Two-loop QED corrections with closed fermion loops are calculated for the 1s bound-electron g factor. Calculations are performed to all orders in the nuclear binding strength parameter Z\alpha (where Z is the nuclear charge and \alpha is…

Atomic Physics · Physics 2015-06-16 V. A. Yerokhin , Z. Harman

We present the two-loop corrected operator matrix elements calculated in N-dimensional regularization up to the finite terms which survive in the limit $\epsilon = N - 4 \to 0 $. The anomalous dimensions of the local operators have been…

High Energy Physics - Phenomenology · Physics 2009-10-31 Y. Matiounine , J. Smith , W. L. van Neerven

We present the two-loop mixed strong-electroweak virtual corrections to the neutral current Drell-Yan process and we provide, in ancillary files, the explicit formulae of the infrared-subtracted finite remainder. The final state collinear…

High Energy Physics - Phenomenology · Physics 2022-06-23 Tommaso Armadillo , Roberto Bonciani , Simone Devoto , Narayan Rana , Alessandro Vicini

We report a calculation of all two-loop QED corrections with closed fermion loops for the n=1 and n=2 states of H-like ions and for a wide range of the nuclear charge numbers Z=1-100. The calculation is performed to all orders in the…

Atomic Physics · Physics 2009-11-13 V. A. Yerokhin , P. Indelicato , V. M. Shabaev

We present the two-loop mixed strong-electroweak virtual corrections to the charged current Drell-Yan process. The final-state collinear singularities are regularised by the lepton mass. The evaluation of all the relevant Feynman integrals,…

High Energy Physics - Phenomenology · Physics 2024-05-02 Tommaso Armadillo , Roberto Bonciani , Simone Devoto , Narayan Rana , Alessandro Vicini

We calculate the unpolarized and polarized two--loop massless off--shell operator matrix elements in QCD to $O(\varepsilon)$ in the dimensional parameter in an automated way. Here we use the method of arbitrary high Mellin moments and…

High Energy Physics - Phenomenology · Physics 2022-05-04 J. Blümlein , P. Marquard , C. Schneider , K. Schönwald

We present our results for the NNLL virtual corrections to the matrix elements of the operators O_1 and O_2 for the inclusive process b\to s\ell^+\ell^- in the kinematical region q^2>4m_c^2, where q^2 is the invariant mass squared of the…

High Energy Physics - Phenomenology · Physics 2009-05-20 Christoph Greub , Volker Pilipp , Christof Schüpbach

We present the complete analytical result for the two-loop logarithmically enhanced contributions to the high energy asymptotic behavior of the vector form factor and the four-fermion cross section in a spontaneously broken SU(2) gauge…

High Energy Physics - Phenomenology · Physics 2010-11-05 Bernd Jantzen , Johann H. Kühn , Alexander A. Penin , Vladimir A. Smirnov

We consider two-loop leading and next-to-leading logarithmic virtual corrections to arbitrary processes with external massless fermions in the electroweak Standard Model at energies well above the electroweak scale. Using the…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. Denner , B. Jantzen , S. Pozzorini

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 present the mixed QCD-EW two-loop virtual amplitudes for the neutral current Drell-Yan production, one of the bottlenecks for the complete calculation of the NNLO mixed QCD-EW corrections. We present the computational details and the…

High Energy Physics - Phenomenology · Physics 2022-08-17 Simone Devoto

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 calculate the complete $O(\alpha^2)$ initial state radiation corrections to $e^+ e^-$ annihilation into a neutral vector boson in a direct analytic computation without any approximation. The corrections are represented in terms of…

High Energy Physics - Phenomenology · Physics 2020-06-24 J. Blümlein , A. De Freitas , C. Raab , K. Schönwald

We present the two-loop corrected operator matrix elements contributing to the scale evolution of the longitudinal spin structure function $g_1(x,Q^2)$ calculated up to finite terms which survive in the limit $\epsilon = N - 4 \to 0$. These…

High Energy Physics - Phenomenology · Physics 2009-10-31 Y. Matiounine , J. Smith , W. L. van Neerven

We report on the three-loop unpolarized and polarized massive operator matrix elements, with single- and two-mass corrections, and the associated deep-inelastic massive Wilson coefficients in the region $Q^2 \gg m_Q^2$, the calculation of…

High Energy Physics - Phenomenology · Physics 2026-02-12 J. Ablinger , A. Behring , J. Blümlein , A. De Freitas , A. von Manteuffel , C. Schneider , K. Schönwald

Recently the two-loop next-to-leading logarithmic (NLL) virtual corrections to arbitrary processes with massless external fermions have been calculated. Within the spontaneously broken electroweak theory the one- and two-loop mass…

High Energy Physics - Phenomenology · Physics 2009-02-16 Bernd Jantzen

We calculate the non-singlet, the pure singlet contribution, and their interference term, at $O(\alpha^2)$ due to electron-pair initial state radiation to $e^+ e^-$ annihilation into a neutral vector boson in a direct analytic computation…

High Energy Physics - Phenomenology · Physics 2019-02-27 J. Blümlein , A. De Freitas , C. G. Raab , K. Schönwald

We present the complete analytical result for the two-loop logarithmically enhanced contributions to the high energy asymptotic behavior of the vector form factor and the four-fermion cross section in a spontaneously broken SU(2) gauge…

High Energy Physics - Phenomenology · Physics 2014-11-18 Bernd Jantzen , Johann H. Kühn , Alexander A. Penin , Vladimir A. Smirnov
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