20180416 10:09 
[PUBDB201801725]
Preprint/Report
Blümlein, J. ; De Freitas, A. ; Schneider, C. ; et al
The Variable Flavor Number Scheme at NexttoLeading Order
[DESY17187; DOTH1730; arXiv:1804.03129]
We present the matching relations of the variable flavor number scheme at nexttoleading 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 twomass effects due to both charm and bottom quarks, having rather similar masses, are important. [...]
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20180410 16:08 
[PUBDB201801662]
Preprint/Report
Ablinger, J. ; Blümlein, J. ; Freitas, A. d. ; et al
The Twomass Contribution to the ThreeLoop Gluonic Operator Matrix Element $A_{gg,Q}^{(3)}$
[DESY 18016, DOTH 18/02]
We calculate the twomass 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. [...]
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20180323 10:10 
[PUBDB201801534]
Preprint/Report
Alekhin, S. ; Blümlein, J. ; Moch, S.
NLO PDFs from the ABMP16 fit
[DESY18026; DOTH 17/28; arXiv:1803.07537]
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 nexttoleading order (NLO) in QCD. The analysis applies the $\overline{\mathrm{MS}}\, $ renormalization scheme for $\alpha_s$ and all quark masses. [...]
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20180312 13:43 
[PUBDB201801455]
Journal Article/Report/Contribution to a conference proceedings
Ablinger, J. ; Blumlein, J. ; Round, M. ; et al
Special functions, transcendentals and their numerics
[DESY17225; arXiv:1712.08541]
13th International Symposium on Radiative Corrections (Applications of Quantum Field Theory to Phenomenology), RADCOR2017, Meeting locationSt. Gilgen, Austria, 25 Sep 2017  29 Sep 20172017092520170929
Proceedings of Science (RADCOR2017), 010 (2017) [10.3204/PUBDB201801455]
Cyclotomic polylogarithms are reviewed and new results concerning the special constants that occur are presented. This also allows some comments on previous literature results using PSLQ..
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ddc:530
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20180219 14:58 
[PUBDB201801245]
Preprint/Report
Ablinger, J. ; Blümlein, J. ; Round, M. ; et al
Special functions, transcendentals and their numerics
[DESY17225; arXiv:1712.08541]
Cyclotomic polylogarithms are reviewed and new results concerning the special constants that occur are presented. This also allows some comments on previous literature results using PSLQ..
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20180119 13:34 
[PUBDB201800697]
Report/Journal Article
Ablinger, J. ; Blümlein, J. ; De Freitas, A. ; et al
The twomass contribution to the threeloop pure singlet operator matrix element
[DESY17195; DOTH1732; arXiv:1711.06717]
We present the twomass QCD contributions to the pure singlet operator matrix element at three loop order in xspace. These terms are relevant for calculating the structure function $F_2(x,Q^2)$ at $O(\alpha_s^3)$ as well as for the matching relations in the variable flavor number scheme and the heavy quark distribution functions at the same order. [...]
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ddc:530
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20180115 15:08 
[PUBDB201800650]
Journal Article/Report/Contribution to a conference proceedings
Ablinger, J. ; Behring, A. ; Blümlein, J. ; et al
Heavy quark form factors at two loops in perturbative QCD
[DESY17188, DOTH 17/31, TTK1736, NIKHEF 2017059]
We present the results for heavy quark form factors at twoloop order in perturbative QCD for different currents, namely vector, axialvector, scalar and pseudoscalar currents, up to second order in the dimensional regularization parameter. We outline the necessary computational details, ultraviolet renormalization and corresponding universal infrared structure..
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20180115 14:52 
[PUBDB201800649]
Journal Article/Report/Contribution to a conference proceedings
Blümlein, J. ; Phan, K. H. ; Riemann, T.
Scalar oneloop vertex integrals as meromorphic functions of spacetime dimension $d$
[KW 17002, DESY 17186, DOTH 17/29]
Representations are derived for the basic scalar oneloop vertex Feynman integrals as meromorphic functions of the spacetime dimension $d$ in terms of (generalized) hypergeometric functions $_2F_1$ and $F_1$. Values at asymptotic or exceptional kinematic points as well as expansions around the singular points at $d=4+2n$, $n$ nonnegative integers, may be derived from the representations easily. [...]
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20180115 08:33 
[PUBDB201800635]
Preprint/Report
Ablinger, J. ; Behring, A. ; Blümlein, J. ; et al
The Heavy Quark Form Factors at Two Loops
[DESY17102; DOTH 17/16; Nikhef 2017063; TTK1744; arXiv:1712.09889]
We compute the twoloop QCD corrections to the heavy quark form factors in case of the vector, axialvector, scalar and pseudoscalar currents up to second order in the dimensional parameter $\epsilon = (4D)/2$. These terms are required in the renormalization of the higher order corrections to these form factors..
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20180111 16:31 
[PUBDB201800554]
Report/Journal Article
Fuster, J. ; Irles, A. ; Melini, D. ; et al
Extracting the topquark running mass using $t\bar{t} + \hbox {1jet}$ events produced at the Large Hadron Collider
[HUEP1705; LAL17034; DESY17053; arXiv:1704.00540]
We present the calculation of the nexttoleading order QCD corrections for topquark pair production in association with an additional jet at hadron colliders, using the modified minimal subtraction scheme to renormalize the topquark mass. The results are compared to measurements at the Large Hadron Collider run I. [...]
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