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Related papers: Heavy-quark QCD vacuum polarisation function: anal…

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Vacuum polarization mediated by quark loops is susceptible to external electromagnetic fields as well as to the QCD vacuum structure. Employing the stochastic vacuum model, we calculate the modification of the one-loop Euler-Heisenberg…

High Energy Physics - Phenomenology · Physics 2007-05-23 H. -Th. Elze , B. Müller , J. Rafelski

The three-loop vacuum polarization function $\Pi(q^2)$ induced by a massive quark is calculated. A comprehensive description of the method is presented. From the imaginary part the ${\cal O}(\alpha_s^2)$ result for the production of heavy…

High Energy Physics - Phenomenology · Physics 2009-10-28 K. G. Chetyrkin , J. H. Kuehn , M. Steinhauser

The three-loop corrections to the potential of two heavy quarks are computed. Analytic results for the most complicated master integrals are presented.

High Energy Physics - Phenomenology · Physics 2010-02-18 Alexander V. Smirnov , Vladimir A. Smirnov , Matthias Steinhauser

We present an analytical calculation of the two-loop QCD corrections to the electromagnetic form factor of heavy quarks. The two-loop contributions to the form factor are reduced to linear combinations of master integrals, which are…

High Energy Physics - Phenomenology · Physics 2009-07-29 J. Gluza , A. Mitov , S. Moch , T. Riemann

We calculate the vacuum polarization functions on the lattice using the overlap fermion formulation.By matching the lattice data at large momentum scales with the perturbative expansion supplemented by Operator Product Expansion (OPE), we…

High Energy Physics - Lattice · Physics 2019-08-13 E. Shintani , S. Aoki , T. W. Chiu , S. Hashimoto , T. H. Hsieh , T. Kaneko , H. Matsufuru , J. Noaki , T. Onogi , N. Yamada

We present the two-loop virtual amplitudes for heavy-quark pair production in light quark-antiquark annihilation and gluon fusion channels, including full spin and color dependence. We use expansions around kinematical limits and numerical…

High Energy Physics - Phenomenology · Physics 2018-04-18 L. Chen , M. Czakon , R. Poncelet

We evaluate the planar two-loop QCD diagrams contributing to the leading color coefficient of the heavy-quark pair production cross section, in the quark-antiquark annihilation channel. We obtain the leading color coefficient in an analytic…

High Energy Physics - Phenomenology · Physics 2009-09-25 R. Bonciani , A. Ferroglia , T. Gehrmann , C. Studerus

We evaluate the two-loop QCD diagrams contributing to the leading color coefficient of the heavy-quark pair production cross section in the gluon fusion channel. We obtain an analytic expression, which is valid for any value of the…

High Energy Physics - Phenomenology · Physics 2011-02-03 R. Bonciani , A. Ferroglia , T. Gehrmann , A. von Manteuffel , C. Studerus

We present the two-loop virtual QCD corrections to the production of heavy quarks in gluon fusion. The results are exact in the limit when all kinematical invariants are large compared to the mass of the heavy quark up to terms suppressed…

High Energy Physics - Phenomenology · Physics 2010-04-05 M. Czakon , A. Mitov , S. Moch

We present the first benchmark evaluation of the two-loop finite remainders for the production of a top-quark pair in association with a jet at hadron colliders in the gluon channel. We work in the leading colour approximation, and perform…

High Energy Physics - Phenomenology · Physics 2025-03-14 Simon Badger , Matteo Becchetti , Colomba Brancaccio , Heribertus Bayu Hartanto , Simone Zoia

We compute the two-loop QCD corrections to the heavy quark form factors in case of the vector, axial-vector, scalar and pseudo-scalar currents up to second order in the dimensional parameter $\epsilon = (4-D)/2$. These terms are required in…

High Energy Physics - Phenomenology · Physics 2018-05-30 J. Ablinger , A. Behring , J. Blümlein , G. Falcioni , A. De Freitas , P. Marquard , N. Rana , C. Schneider

We review algorithmic methods for two-loop calculations in HQET, and the analogous methods for on-shell QCD, needed for matching HQET to QCD.

High Energy Physics - Phenomenology · Physics 2007-05-23 D. J. Broadhurst , A. G. Grozin

We present a complete set of analytic helicity amplitudes for top quark pair production via gluon fusion at two-loops in QCD. For the first time, we include corrections due to massive fermion loops which give rise to integrals over elliptic…

High Energy Physics - Phenomenology · Physics 2021-07-14 Simon Badger , Ekta Chaubey , Heribertus Bayu Hartanto , Robin Marzucca

We compute two-loop helicity amplitudes in QCD for diphoton production through quark- and gluon-initiated channels, accounting for a massive internal quark loop by keeping its full mass dependence. Using physical projectors, we directly…

High Energy Physics - Phenomenology · Physics 2025-02-06 Taushif Ahmed , Amlan Chakraborty , Ekta Chaubey , Mandeep Kaur

The charm-quark mass is typically not so far from the cutoff 1/a in lattice simulations. Its determinant may then potentially introduce large cutoff effects. We choose the O(a)-improved Wilson formulation and compute the vacuum polarization…

High Energy Physics - Lattice · Physics 2012-03-13 Andreas Athenodorou

We consider the currents formed by a heavy and a light quark within Quantum Chromodynamics and compute the matching to Heavy Quark Effective Theory to three-loop accuracy. As an application we obtain the third-order perturbative corrections…

High Energy Physics - Phenomenology · Physics 2010-04-30 S. Bekavac , A. G. Grozin , P. Marquard , J. H. Piclum , D. Seidel , M. Steinhauser

We present the first computation of the complete two-loop, fully-differential soft function describing the production of a heavy-quark pair in association with a color-singlet system at hadron colliders. This result constitutes one of the…

High Energy Physics - Phenomenology · Physics 2025-12-01 Ze Long Liu , Pier Francesco Monni

Lattice QCD results relevant to heavy quark physics are reviewed. In particular new results will be shown that, for the first time, include dynamical quarks in the QCD vacuum which are close enough to being realistic to allow accurate…

High Energy Physics - Phenomenology · Physics 2010-11-23 Christine Davies

We study the renormalized free energy of a heavy quark anti-quark pair in the different colour channels in full QCD at finite temperature. Similarities and differences to the quenched case are discussed and the temperature dependence as…

High Energy Physics - Lattice · Physics 2008-11-26 Olaf Kaczmarek , Shinji Ejiri , Frithjof Karsch , Edwin Laermann , Felix Zantow

We present the two-loop virtual QCD corrections to the production of heavy quarks in the quark--anti-quark--annihilation channel in the limit when all kinematical invariants are large compared to the mass of the heavy quark. Our result is…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. Czakon , A. Mitov , S. Moch