# ZEU-THEO

 2019-03-1811:32 [PUBDB-2019-01570] Report/Journal Article Riemann, T. Scalar 1-loop Feynman integrals as meromorphic functions in space-time dimension d [DESY 17-079, HCMUS-19-01, KW 18-004, arXiv:1812.10975] Physics letters / B 791, 257 - 264 (2019) [10.1016/j.physletb.2019.02.044]   The long-standing problem of representing the general massive one-loop Feynman integral as a meromorphic function of the space-time dimension d has been solved for the basis of scalar one- to four-point functions with indices one. In 2003 the solution of difference equations in the space-time dimension allowed to determine the necessary classes of special functions: self-energies need ordinary logarithms and Gauss hypergeometric functions $_{2}F_1$, vertices need additionally Kampé de Fériet-Appell functions $F_1$, and box integrals also Lauricella-Saran functions $F_S$ [...] OpenAccess: PDF PDF (PDFA); 2019-03-1415:57 [PUBDB-2019-01551] Preprint/Report Marquard, P. Five-Loop Static Contribution to the Gravitational Interaction Potential of Two Point Masses [arXiv:1902.11180; DESY-19-029; DO-TH-19/01]   We compute the static contribution to the gravitational interaction potential of two point masses in the velocity-independent five-loop (and 5th post-Newtonian) approximation to the harmonic coordinates effective action in a direct calculation. The computation is performed using effective field methods based on Feynman diagrams in momentum-space in $d = 3 - 2\varepsilon$ space dimensions. [...] OpenAccess: PDF PDF (PDFA); 2019-03-1415:55 [PUBDB-2019-01550] Preprint/Report et al HEJ 2: High Energy Resummation for Hadron Colliders [arXiv:1902.08430; DESY-19-028; IPPP/19/13; MCnet-19-05]   We present HEJ 2, a new implementation of the High Energy Jets formalism for high-energy resummation in hadron-collider processes as a flexible Monte Carlo event generator. In combination with a conventional fixed-order event generator, HEJ 2 can be used to obtain greatly improved predictions for a number of phenomenologically important processes by adding all-order logarithmic corrections in $\hat{s}/p_\perp^2$. [...] OpenAccess: PDF PDF (PDFA); 2019-03-1411:38 [PUBDB-2019-01537] Report/Journal Article et al The $O(\alpha^2)$ Initial State QED Corrections to $e^+e^-$ Annihilation to a Neutral Vector Boson Revisited [arXiv:1901.08018; DESY-18-226; DO-TH-18-30] Physics letters / B 791, 206 - 209 (2019) [10.1016/j.physletb.2019.02.038]   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 without any approximation. The correction is represented in terms of iterated incomplete elliptic integrals. [...] OpenAccess: PDF PDF (PDFA); 2019-02-0413:24 [PUBDB-2019-00934] Journal Article Rana, N. Asymptotic behavior of the heavy quark form factors at higher order Physical review / D 99(1), 016013 (2019) [10.1103/PhysRevD.99.016013]   In the asymptotic limit $Q^2 ≫ m^2$, the heavy quark form factors exhibit Sudakov behavior. We study the corresponding renormalization group equations of the heavy quark form factors which do not only govern the structure of infrared divergences but also control the high energy logarithms [...] OpenAccess: PDF PDF (PDFA); 2019-01-2812:22 [PUBDB-2019-00778] Preprint/Report et al The $O(\alpha^2)$ Initial State QED Corrections to $e^+e^-$ Annihilation to a Neutral Vector Boson Revisited [arXiv:1901.08018; DESY-18-226; DO-TH-18-30]   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 without any approximation. The correction is represented in terms of iterated incomplete elliptic integrals. [...] OpenAccess: PDF PDF (PDFA); 2019-01-1814:08 [PUBDB-2019-00612] Preprint/Report Riemann, T. Scalar 1-loop Feynman integrals as meromorphic functions in space-time dimension d [DESY-17-079; HCMUS-19-01; KW-18-004; arXiv:1812.10975]   The long-standing problem of representing the general massive one-loop Feynman integral as a meromorphic function of the space-time dimension $d$ has been solved for the basis of scalar one- to four-point functions with indices one. In 2003 the solution of difference equations in the space-time dimension allowed to determine the necessary classes of special functions: self-energies need ordinary logarithms and Gauss hypergeometric functions $_2F_1$, vertices need additionally Kamp\'{e} de F\'{e}riet-Appell functions $F_1$, and box integrals also Lauricella-Saran functions $F_S$. [...] OpenAccess: PDF PDF (PDFA); 2019-01-1415:05 [PUBDB-2019-00442] Preprint/Report et al Two-loop QCD corrections to $\mathrm{b + \bar{b} \rightarrow H+H}$ amplitude [arXiv:1811.01853; DESY-18–166; TIF-UNIMI-2018-9]   We present the first results on the two-loop massless QCD corrections to the four-point amplitude $b+\overline{b} \rightarrow H+H$ in the five flavour scheme, treating bottom quarks as massless. This amplitude is sensitive to the trilinear Higgs boson coupling. [...] OpenAccess: PDF PDF (PDFA); 2019-01-0814:38 [PUBDB-2019-00122] Report/Journal Article et al Four-loop wave function renormalization in QCD and QED [DESY-18-011; TTP18-007; arXiv:1801.08292] Physical review / D 97(5), 054032 (2018) [10.1103/PhysRevD.97.054032]   We compute the on-shell wave function renormalization constant to four-loop order in QCD and present numerical results for all coefficients of the $SU(N_c )$ color factors. We extract the four-loop Heavy Quark Effective Theory anomalous dimension of the heavy-quark field and also discuss the application of our result to QED.. OpenAccess: PDF PDF (PDFA); 2019-01-0212:39 [PUBDB-2019-00005] Journal Article et al Automated solution of first order factorizable systems of differential equations in one variable Nuclear physics 939, 253 - 291 (2019) [10.1016/j.nuclphysb.2018.12.010]   We present an algorithm which allows to solve analytically linear systems of differential equations which factorize to first order. The solution is given in terms of iterated integrals over an alphabet where its structure is implied by the coefficient matrix of the differential equations [...] OpenAccess: PDF PDF (PDFA);