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Related papers: The $n_f^2$ contributions to fermionic four-loop f…

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We have computed the first 30 even-N moments for the double fermionic (nf^2) part of the quark-to-gluon splitting function P_{gq} at the fourth order of perturbative QCD via the renormalization of off-shell operator matrix elements. From…

High Energy Physics - Phenomenology · Physics 2023-10-06 G. Falcioni , F. Herzog , S. Moch , J. Vermaseren , A. Vogt

We compute the two-loop corrections to the massless quark form factor $\gamma^* \to q\bar q$ and gluon form factor $H\to gg$ to all orders in the dimensional regularisation parameter $\epsilon=(4-d)/2$. The two-loop contributions to the…

High Energy Physics - Phenomenology · Physics 2021-11-04 T. Gehrmann , T. Huber , D. Maitre

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…

High Energy Physics - Phenomenology · Physics 2018-08-01 J. Ablinger , J. Blümlein , P. Marquard , N. Rana , C. Schneider

We present the computation of the two-loop form factors for diphoton production in the quark annihilation channel. These quantities are relevant for the NNLO QCD corrections to diphoton production at LHC recently presented in…

High Energy Physics - Phenomenology · Physics 2023-08-23 Matteo Becchetti , Roberto Bonciani , Leandro Cieri , Federico Coro , Federico Ripani

We compute the form factors of the photon-quark-anti-quark vertex and the effective vertex of a Higgs boson and two gluons to three-loop order within massless perturbative Quantum Chromodynamics. These results provide building blocks for…

High Energy Physics - Phenomenology · Physics 2009-06-30 P. A. Baikov , K. G. Chetyrkin , A. V. Smirnov , V. A. Smirnov , M. Steinhauser

We perform a high statistics calculation of disconnected fermion loops on Graphics Processing Units for a range of nucleon matrix elements extracted using lattice QCD. The isoscalar electromagnetic and axial vector form factors, the…

High Energy Physics - Lattice · Physics 2014-02-12 A. Abdel-Rehim , C. Alexandrou , M. Constantinou , V. Drach , K. Hadjiyiannakou , K. Jansen , G. Koutsou , A. Vaquero

We compute the four-loop QCD corrections to the massless quark-anti-quark-photon form factor $F_q$ in the large-$N_c$ limit. From the pole part we extract analytic expressions for the corresponding cusp and collinear anomalous dimensions.

High Energy Physics - Phenomenology · Physics 2017-04-26 Johannes Henn , Roman N. Lee , Alexander V. Smirnov , Vladimir A. Smirnov , Matthias Steinhauser

We present results on the isovector and isoscalar nucleon axial form factors including disconnected contributions,using an ensemble of $N_f =2$ twisted mass clover- improved Wilson fermions simulated with approximately the physical value of…

We have determined the fourth-order $n_f$ contributions to the two splitting functions governing the evolution of all flavor differences of quark distributions of hadrons in perturbative quantum chromodynamics with $n_f$ light flavors. The…

High Energy Physics - Phenomenology · Physics 2025-05-16 B. A. Kniehl , S. Moch , V. N. Velizhanin , A. Vogt

We report on the complete three-loop corrections to the Higgs-gluon form factor in QCD. While previous calculations are based on QCD with a single heavy quark of arbitrary mass, we extend the study to QCD involving two different massive…

High Energy Physics - Phenomenology · Physics 2024-02-28 Marco Niggetiedt , Johann Usovitsch

We calculate the full set of the two-loop master integrals for heavy-to-light form factors of two different massive fermions for arbitrary momentum transfer in NNLO QCD or QED corrections. These integrals allow to determine the two-loop QCD…

High Energy Physics - Phenomenology · Physics 2018-04-04 Long-Bin Chen

The massive 3-loop fermion-loop corrections $\propto C_A N_f T_F^2$ and $C_F N_f T_F^2$ to the massive operator matrix elements $A_{Qg}$, $A_{Qq}^{\rm{PS}}$, $A_{qq,Q}^{\rm{PS}}$, $A_{qq,Q}^{\rm{NS}}$ and $A_{qq,Q}^{\rm{NS,TR}} have been…

High Energy Physics - Phenomenology · Physics 2010-10-21 Fabian Wissbrock

We compute the eighth-order fermionic corrections involving two and three closed massless fermion loops to the anomalous magnetic moment of the muon. The required four-loop on-shell integrals are classified and explicit analytical results…

High Energy Physics - Phenomenology · Physics 2015-06-12 Roman Lee , Peter Marquard , Alexander V. Smirnov , Vladimir A. Smirnov , Matthias Steinhauser

We give the analytic expressions of the eight master integrals entering our previous computation of two-loop light fermion contributions to $gg \to H$ and $H \to \gamma\gamma$. The results are expressed in terms of generalized harmonic…

High Energy Physics - Phenomenology · Physics 2009-11-10 U. Aglietti , R. Bonciani , G. Degrassi , A. Vicini

We compute three-loop corrections of $\mathcal{O}(\alpha_{s}^3)$ to form factors with one massive and one massless quark coupling to an external vector, axialvector, scalar, pseudoscalar, or tensor current. We obtain analytic results for…

High Energy Physics - Phenomenology · Physics 2024-09-24 Matteo Fael , Tobias Huber , Fabian Lange , Jakob Müller , Kay Schönwald , Matthias Steinhauser

We have calculated the n_f^2 and n_f^3 contributions to the flavour non-singlet structure functions F_2 and F_L in inclusive deep-inelastic scattering at the fourth order in the strong coupling alpha_s. The coefficient functions have been…

High Energy Physics - Phenomenology · Physics 2023-04-12 A. Basdew-Sharma , A. Pelloni , Franz Herzog , A. Vogt

We compute the fermionic (n_f) contributions to the flavour non-singlet structure functions in unpolarized electromagnetic deep-inelastic scattering at third order of massless perturbative QCD. Complete results are presented for the…

High Energy Physics - Phenomenology · Physics 2010-04-05 S. Moch , J. A. M. Vermaseren , A. Vogt

We compute the three-loop non-singlet corrections to the photon-quark form factors taking into account the full dependence on the virtuality of the photon and the quark mass. We combine the method of differential equations in an effective…

High Energy Physics - Phenomenology · Physics 2022-05-11 Matteo Fael , Fabian Lange , Kay Schoenwald , Matthias Steinhauser

We present the color planar and complete light quark QCD contributions to the three loop heavy quark form factors in the case of vector, axial-vector, scalar and pseudo-scalar currents. We evaluate the master integrals applying a new method…

High Energy Physics - Phenomenology · Physics 2018-07-18 Jakob Ablinger , Johannes Bluemlein , Peter Marquard , Narayan Rana , Carsten Schneider

Recently two-loop electroweak corrections to the neutral current four-fermion processes at high energies have been presented. The basic ingredient of this calculation is the evaluation of the two-loop corrections to the Abelian vector form…

High Energy Physics - Phenomenology · Physics 2009-01-07 Bernd Jantzen , Vladimir A. Smirnov