# ZEU-THEO

 2018-08-0114:57 [PUBDB-2018-02739] Report/Journal Article Moch, S.-O. NLO PDFs from the ABMP16 fit [arXiv:1803.07537, DESY-18-026, DO-TH-17-28]   We perform a global fit of parton distribution functions (PDFs) together with the strong coupling constant $\alpha_s$ and the quark masses $m_c, m_b$ and $m_t$ at next-to-leading order (NLO) in QCD. The analysis applies the $\overline{MS}$ renormalization scheme for αs and all quark masses. [...] OpenAccess: PDF PDF (PDFA); 2018-07-0915:33 [PUBDB-2018-02557] Journal Article et al Iterated elliptic and hypergeometric integrals for Feynman diagrams Journal of mathematical physics 59(6), 062305 (2018) [10.1063/1.4986417]   We calculate 3-loop master integrals for heavy quark correlators and the 3-loop quantum chromodynamics corrections to the $ρ$-parameter. They obey non-factorizing differential equations of second order with more than three singularities, which cannot be factorized in Mellin-N space either. [...] Published on 2018-06-28. Available in OpenAccess from 2019-06-28.: PDF PDF (PDFA); 2018-06-2513:29 [PUBDB-2018-02375] Journal Article Schneider, C. Analytic computing methods for precision calculations in quantum field theory International journal of modern physics / A 33(17), 1830015 - (2018) [10.1142/S0217751X18300156]   An overview is presented on the current status of main mathematical computation methods for the multiloop corrections to single-scale observables in quantum field theory and the associated mathematical number and function spaces and algebras. At present, massless single-scale quantities can be calculated analytically in QCD to 4-loop order and single mass and double mass quantities to 3-loop order, while zero-scale quantities have been calculated to 5-loop order. [...] Restricted: PDF PDF (PDFA); 2018-06-2513:23 [PUBDB-2018-02372] Journal Article et al Heavy quark form factors at three loops in the planar limit Physics letters / B 782, 528 - 532 (2018) [10.1016/j.physletb.2018.05.077]   We compute the color-planar and complete light quark non-singlet contributions to the heavy quark form factors in the case of the axialvector, scalar and pseudoscalar currents at three loops in perturbative QCD. We evaluate the master integrals applying a new method based on differential equations for general bases, which is applicable for all first order factorizing systems [...] OpenAccess: PDF PDF (PDFA); 2018-06-1816:24 [PUBDB-2018-02323] Journal Article Marquard, P. Validity of Padé approximations in vacuum polarization at three- and four-loop order Physical review / D 97(5), 056016 (2018) [10.1103/PhysRevD.97.056016]   The heavy-quark contribution to the polarization function Π at higher perturbative orders is presently only known approximately. We scrutinize the accuracy of state-of-the-art approximations at three- and four-loop order. [...] OpenAccess: PDF PDF (PDFA); 2018-06-0414:58 [PUBDB-2018-02179] Report/Journal Article et al The Two-mass Contribution to the Three-Loop Gluonic Operator Matrix Element $A_{gg,Q}^{(3)}$ [DESY-18-016; DO-TH-18-02; arXiv:1804.02226] Nuclear physics / B 932, 129 - 240 (2018) [10.1016/j.nuclphysb.2018.04.023]   We calculate the two-mass QCD contributions to the massive operator matrix element $A_{gg,Q}$ at $\mathcal{O} (\alpha_s^3)$ in analytic form in Mellin $N$- and $z$-space, maintaining the complete dependence on the heavy quark mass ratio. These terms are important ingredients for the matching relations of the variable flavor number scheme in the presence of two heavy quark flavors, such as charm and bottom. [...] OpenAccess: PDF PDF (PDFA); 2018-06-0414:51 [PUBDB-2018-02178] Report/Journal Article et al Heavy quark form factors at two loops [DESY-17-102; DO-TH-17-16; Nikhef-2017-063; TTK-17-44; arXiv:1712.09889] Physical review / D 97(9), 094022 (2018) [10.1103/PhysRevD.97.094022]   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 the renormalization of the higher order corrections to these form factors.. OpenAccess: PDF PDF (PDFA); 2018-06-0109:46 [PUBDB-2018-02167] Journal Article et al The variable flavor number scheme at next-to-leading order Physics letters / B 782, 362 - 366 (2018) [10.1016/j.physletb.2018.05.054]   We present the matching relations of the variable flavor number scheme at next-to-leading order, which are of importance to define heavy quark partonic distributions for the use at high energy colliders such as Tevatron and the LHC. The consideration of the two-mass effects due to both charm and bottom quarks, having rather similar masses, are important [...] OpenAccess: PDF PDF (PDFA); 2018-05-2814:41 [PUBDB-2018-02123] Preprint/Report et al Five-loop renormalisation of QCD in covariant gauges [DESY-17-144; Nikhef-2017-42; arXiv:1709.08541]   We present the complete set of vertex, wave function and charge renormalisation constants in QCD in a general simple gauge group and with the complete dependence on the covariant gauge parameter ξ in the minimal subtraction scheme of conventional dimensional regularisation. Our results confirm all already known results, which were obtained in the Feynman gauge, and allow the extraction of other useful gauges such as the Landau gauge. [...] OpenAccess: PDF PDF (PDFA); 2018-05-0210:39 [PUBDB-2018-01884] Preprint/Report Jegerlehner, F. The Muon g-2 in Progress [DESY-18-057; HU-EP-18-11; arXiv:1804.07409]   Two next generation muon $g-2$ experiments at Fermilab in the US and at J-PARC in Japan have been designed to reach a four times better precision from 0.54 ppm to 0.14 ppm and the challenge for the theory side is to keep up in precision as far as possible. This has triggered a lot of new research activities. [...] OpenAccess: PDF PDF (PDFA);