20170919 10:04 
[PUBDB201710870]
Report/Journal Article
Dubovyk, I. ; Freitas, A. ; Gluza, J. ; et al
The twoloop electroweak bosonic corrections to $\sin^2\theta_{\textrm{eff}}^{\textrm{b}}$
[DESY16119; KW16002; arXiv:1607.08375]
ddc:530
The prediction of the effective electroweak mixing angle $\sin^2\theta_{\rm eff}^{\rm b}$ in the Standard Model at twoloop accuracy has now been completed by the first calculation of the bosonic twoloop corrections to the $Z{\bar b}b$ vertex. Numerical predictions are presented in the form of a fitting formula as function of $M_Z, M_W, M_H, m_t$ and $\Delta{\alpha}$, ${\alpha_{\rm s}}$. [...]
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20170801 11:08 
[PUBDB201708782]
Report/Journal Article
Alekhin, S. ; Blümlein, J. ; Moch, S. ; et al
Parton distribution functions, $\alpha_s$, and heavyquark masses for LHC Run II
[DESY16179, DOTH1613, arXiv:1701.05838]
ddc:530
We determine a new set of parton distribution functions (ABMP16), the strong coupling constant $\alpha_s$ and the quark masses $m_c$, $m_b$ and $m_t$ in a global fit to nexttonexttoleading order (NNLO) in QCD. The analysis uses the $\overline{MS}$ scheme for $\alpha_s$ and all quark masses and is performed in the fixedflavor number scheme for $n_f = 3, 4, 5$. [...]
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20170717 10:46 
[PUBDB201707732]
Journal Article
Ablinger, J. ; Behring, A. ; Blümlein, J. ; et al
The threeloop splitting functions P q g ( 2 ) and P g g ( 2 , N F )
ddc:530
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20170703 14:52 
[PUBDB201706699]
Report/Journal Article
Jegerlehner, F. ; Kołodziej, K.
Photon radiation in $e^+e^\to$ hadrons at low energies with carlomat_3.1
[DESY17001; HUEP1701; arXiv:1701.01837]
ddc:530
We present a sample of results for the cross sections of several processes of low energetic $e^+e^$ annihilation into final states containing pions accompanied by one or two photons, or a light lepton pair. The results, which have been obtained with a new version of a multipurpose Monte Carlo program CARLOMAT, labelled 3.1, demonstrate new capabilities of the program which, among others, include a possibility of taking into account either the initial or final state radiation separately, or both at a time, and a possibility of inclusion of the electromagnetic charged pion form factor for processes with charged pion pairs. [...]
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20170619 13:43 
[PUBDB201705452]
Report/Journal Article
Moch, S. ; Vermaseren, J. A. M. ; Vogt, A.
On ${\gamma }_{5}$ in higherorder QCD calculations and the NNLO evolution of the polarized valence distribution
[DESY15061; NIKHEF15018; LTH1042; arXiv:1506.04517]
ddc:530
We discuss the prescription for the Dirac matrix ${\gamma }_{5}$ in dimensional regularization used in most second and thirdorder QCD calculations of collider cross sections. We provide an alternative implementation of this approach that avoids the use of an explicit form of ${\gamma }_{5}$ and of its (anti) commutation relations in the most important case of no more than one ${\gamma }_{5}$ in each fermion trace. [...]
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20170614 14:42 
[PUBDB201704944]
Report/Journal Article
Behring, A. ; Blümlein, J. ; Falcioni, G. ; et al
Asymptotic 3loop heavy flavor corrections to the charged current structure functions $F^{W^{+}W^{}}_{L}(x,Q^{2})$ and $F^{W^{+}W^{}}_{2}(x,Q^{2})$
[DESY16148; DOTH1615; arXiv:1609.06255]
ddc:530
We calculate the massive Wilson coefficients for the heavy flavor contributions to the nonsinglet charged current deepinelastic scattering structure functions $F_L^{W^+}(x,Q^2)F_L^{W^}(x,Q^2)$ and $F_2^{W^+}(x,Q^2)F_2^{W^}(x,Q^2)$ in the asymptotic region $Q^2 \gg m^2$ to 3loop order in Quantum Chromodynamics (QCD) at general values of the Mellin variable $N$ and the momentum fraction $x$. Besides the heavy quark pair production, also the single heavy flavor excitation $s \rightarrow c$ contributes. [...]
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20170613 16:14 
[PUBDB201704838]
Preprint/Report
Blümlein, J. ; Round, M. ; Schneider, C.
Refined Holonomic Summation Algorithms in Particle Physics
[DESY17087; DOTH1709; arXiv:1706.03677]
An improved multisummation approach is introduced and discussed that enables one to simultaneously handle indefinite nested sums and products in the setting of difference rings and holonomic sequences. Relevant mathematics is reviewed and the underlying advanced difference ring machinery is elaborated upon. [...]
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20170606 13:38 
[PUBDB201704322]
Report/Journal Article
Blümlein, J. ; Schneider, C.
The method of arbitrarily large moments to calculate single scale processes in quantum field theory
[DESY17009; DOTH 1701; arXiv:1701.04614]
ddc:530
We device a new method to calculate a large number of Mellin moments of single scale quantities using the systems of differential and/or difference equations obtained by integrationbyparts identities between the corresponding Feynman integrals of loop corrections to physical quantities. These scalar quantities have a much simpler mathematical structure than the complete quantity. [...]
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20170606 11:46 
[PUBDB201704277]
Preprint/Report
Ablinger, J. ; Blümlein, J. ; De Freitas, A. ; et al
Three Loop Massive Operator Matrix Elements and Asymptotic Wilson Coefficients with Two Different Masses
[DESY14019; DOTH1508; arXiv:1705.07030]
Starting at 3loop order, the massive Wilson coefficients for deepinelastic scattering and the massive operator matrix elements describing the variable flavor number scheme receive contributions of Feynman diagrams carrying quark lines with two different masses. In the case of the charm and bottom quarks, the usual decoupling of one heavy mass at a time no longer holds, since the ratio of the respective masses, $\eta = m_c^2/m_b^2 \sim 1/10$, is not small enough. [...]
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20170606 11:38 
[PUBDB201704273]
Preprint/Report
Ablinger, J. ; Blümlein, J. ; De Freitas, A. ; et al
Iterated Elliptic and Hypergeometric Integrals for Feynman Diagrams
[DESY16147; DOTH1614; arXiv:1706.01299]
We calculate 3loop master integrals for heavy quark correlators and the 3loop QCD corrections to the $\rho$parameter. They obey nonfactorizing differential equations of second order with more than three singularities, which cannot be factorized in Mellin$N$ space either. [...]
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