20190318 11:32 
[PUBDB201901570]
Report/Journal Article
Phan, K. H. ; Riemann, T.
Scalar 1loop Feynman integrals as meromorphic functions in spacetime dimension d
[DESY 17079, HCMUS1901, KW 18004, arXiv:1812.10975]
The longstanding problem of representing the general massive oneloop Feynman integral as a meromorphic function of the spacetime dimension d has been solved for the basis of scalar one to fourpoint functions with indices one. In 2003 the solution of difference equations in the spacetime dimension allowed to determine the necessary classes of special functions: selfenergies need ordinary logarithms and Gauss hypergeometric functions $_{2}F_1$, vertices need additionally Kampé de FérietAppell functions $F_1$, and box integrals also LauricellaSaran functions $F_S$ [...]
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ddc:530
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20190314 15:57 
[PUBDB201901551]
Preprint/Report
Blümlein, J. ; Maier, A. M. ; Marquard, P.
FiveLoop Static Contribution to the Gravitational Interaction Potential of Two Point Masses
[arXiv:1902.11180; DESY19029; DOTH19/01]
We compute the static contribution to the gravitational interaction potential of two point masses in the velocityindependent fiveloop (and 5th postNewtonian) approximation to the harmonic coordinates effective action in a direct calculation. The computation is performed using effective field methods based on Feynman diagrams in momentumspace in $d = 3  2\varepsilon$ space dimensions. [...]
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20190314 15:55 
[PUBDB201901550]
Preprint/Report
Andersen, J. R. ; Hapola, T. ; Heil, M. ; et al
HEJ 2: High Energy Resummation for Hadron Colliders
[arXiv:1902.08430; DESY19028; IPPP/19/13; MCnet1905]
We present HEJ 2, a new implementation of the High Energy Jets formalism for highenergy resummation in hadroncollider processes as a flexible Monte Carlo event generator. In combination with a conventional fixedorder event generator, HEJ 2 can be used to obtain greatly improved predictions for a number of phenomenologically important processes by adding allorder logarithmic corrections in $\hat{s}/p_\perp^2$. [...]
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20190314 11:38 
[PUBDB201901537]
Report/Journal Article
Blümlein, J. ; De Freitas, A. ; Raab, C. G. ; et al
The $O(\alpha^2)$ Initial State QED Corrections to $e^+e^$ Annihilation to a Neutral Vector Boson Revisited
[arXiv:1901.08018; DESY18226; DOTH1830]
We calculate the nonsinglet, the pure singlet contribution, and their interference term, at $O(\alpha^2)$ due to electronpair 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. [...]
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ddc:530
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20190204 13:24 
[PUBDB201900934]
Journal Article
Blümlein, J. ; Marquard, P. ; Rana, N.
Asymptotic behavior of the heavy quark form factors at higher order
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 [...]
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ddc:530
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20190128 12:22 
[PUBDB201900778]
Preprint/Report
Blümlein, J. ; De Freitas, A. ; Raab, C. G. ; et al
The $O(\alpha^2)$ Initial State QED Corrections to $e^+e^$ Annihilation to a Neutral Vector Boson Revisited
[arXiv:1901.08018; DESY18226; DOTH1830]
We calculate the nonsinglet, the pure singlet contribution, and their interference term, at $O(\alpha^2)$ due to electronpair 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. [...]
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20190118 14:08 
[PUBDB201900612]
Preprint/Report
Phan, K. H. ; Riemann, T.
Scalar 1loop Feynman integrals as meromorphic functions in spacetime dimension d
[DESY17079; HCMUS1901; KW18004; arXiv:1812.10975]
The longstanding problem of representing the general massive oneloop Feynman integral as a meromorphic function of the spacetime dimension $d$ has been solved for the basis of scalar one to fourpoint functions with indices one. In 2003 the solution of difference equations in the spacetime dimension allowed to determine the necessary classes of special functions: selfenergies need ordinary logarithms and Gauss hypergeometric functions $_2F_1$, vertices need additionally Kamp\'{e} de F\'{e}rietAppell functions $F_1$, and box integrals also LauricellaSaran functions $F_S$. [...]
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20190114 15:05 
[PUBDB201900442]
Preprint/Report
H, A. A. ; Banerjee, P. ; Chakraborty, A. ; et al
Twoloop QCD corrections to $\mathrm{b + \bar{b} \rightarrow H+H}$ amplitude
[arXiv:1811.01853; DESY18–166; TIFUNIMI20189]
We present the first results on the twoloop massless QCD corrections to the fourpoint 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. [...]
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20190108 14:38 
[PUBDB201900122]
Report/Journal Article
Marquard, P. ; Smirnov, A. V. ; Smirnov, V. A. ; et al
Fourloop wave function renormalization in QCD and QED
[DESY18011; TTP18007; arXiv:1801.08292]
We compute the onshell wave function renormalization constant to fourloop order in QCD and present numerical results for all coefficients of the $SU(N_c )$ color factors. We extract the fourloop Heavy Quark Effective Theory anomalous dimension of the heavyquark field and also discuss the application of our result to QED..
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ddc:530
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20190102 12:39 
[PUBDB201900005]
Journal Article
Ablinger, J. ; Blümlein, J. ; Marquard, P. ; et al
Automated solution of first order factorizable systems of differential equations in one variable
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 [...]
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