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Related papers: Four-loop splitting functions in QCD -- The gluon-…

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We use on-shell recursion relations to compute analytically the one-loop corrections to maximally-helicity-violating n-gluon amplitudes in QCD. The cut-containing parts have been computed previously; our work supplies the remaining rational…

High Energy Physics - Phenomenology · Physics 2008-11-26 Carola F. Berger , Zvi Bern , Lance J. Dixon , Darren Forde , David A. Kosower

We compute the quark and gluon transverse momentum dependent parton distribution functions at next-to-next-to-next-to-leading order (N$^3$LO) in perturbative QCD. Our calculation is based on an expansion of the differential Higgs boson and…

High Energy Physics - Phenomenology · Physics 2020-10-28 Markus A. Ebert , Bernhard Mistlberger , Gherardo Vita

In this work, we investigate the gluon distribution functions for the pion and kaon, in addition to the improved result of the valence-quark ones, in the gauge-invariant nonlocal chiral-quark model (NL$\chi$QM), in which the momentum…

High Energy Physics - Phenomenology · Physics 2023-02-14 Parada T. P. Hutauruk , Seung-il Nam

We calculate the transverse momentum dependent gluon-to-gluon splitting function within kT-factorization [EPJC 78 (2018) 174], generalizing the framework of [NPB 175 (1980) 27; NPB 427 (1994) 475] and extending our previous works [JHEP 01…

High Energy Physics - Phenomenology · Physics 2018-08-07 A. Kusina , M. Hentschinski , K. Kutak , M. Serino

In the limit where partons become collinear to each other, scattering amplitudes factorize into a product of universal, process-independent building blocks and scattering amplitudes involving fewer partons. We compute these universal…

High Energy Physics - Phenomenology · Physics 2024-08-07 Xin Guan , Franz Herzog , Yao Ma , Bernhard Mistlberger , Adi Suresh

The semi-inclusive decay processes of a top quark into a charged pseudo-scalar meson and a jet are studied within the framework of QCD factorization. The leading power of the decay matrix elements can be factorized into heavy-to-light quark…

High Energy Physics - Phenomenology · Physics 2025-04-02 Long-Shun Lu , Lei-Yi Li , Cai-Dian Lü

We present the O(as^4) virtual QCD corrections to unlike-quark and like-quark scattering due to the interference of one-loop amplitudes with one-loop amplitudes. The structure of the infrared divergences agrees with that predicted by…

High Energy Physics - Phenomenology · Physics 2008-11-26 C. Anastasiou , E. W. N. Glover , C. Oleari , M. E. Tejeda-Yeomans

We present a general formalism for computing the matrix-element squared for the emission of soft energy-ordered gluons beyond two loops in QCD perturbation theory at finite $N_c$. Our formalism is valid in the eikonal approximation. A…

High Energy Physics - Phenomenology · Physics 2016-03-24 Yazid Delenda , Kamel Khelifa-Kerfa

Starting from the QCD Schroedinger functional (SF), we define a family of renormalization schemes for two four-quark operators, which are, in the chiral limit, protected against mixing with other operators. With the appropriate flavour…

High Energy Physics - Lattice · Physics 2015-06-25 F. Palombi , C. Pena , S. Sint

We compute the 3-loop O(\alpha \alpha_s) correction to the Higgs boson production cross section arising from light quarks using an effective theory approach. Our calculation probes the factorization of QCD and electroweak perturbative…

High Energy Physics - Phenomenology · Physics 2010-01-15 Charalampos Anastasiou , Radja Boughezal , Frank Petriello

Within the Quark-Gluon String Model A.B. Kaidalov found a behaviour of quark and diquark fragmentation functions for $z\rightarrow 0$ and $z\rightarrow 1$, and proposed interpolation formulae for the functions in the whole region of $z$.…

High Energy Physics - Phenomenology · Physics 2018-06-06 V. Uzhinsky , A. Galoyan

We have calculated the complete matrix of three-loop helicity-difference (`polarized') splitting functions Delta P_ik^(2), i,k = q,g, in massless perturbative QCD. In this note we briefly discuss some properties of the polarized splitting…

High Energy Physics - Phenomenology · Physics 2014-05-15 A. Vogt , S. Moch , J. A. M. Vermaseren

We calculate the next-to-next-to-leading order ${\cal O}(\alpha_s^4)$ one-loop squared corrections to the production of heavy-quark pairs in the gluon-gluon fusion process. Together with the previously derived results on the $q \bar{q}$…

High Energy Physics - Phenomenology · Physics 2008-12-18 B. Kniehl , J. G. Körner , Z. Merebashvili , M. Rogal

Toponium production at future hadron colliders is investigated. Perturbative QCD corrections to the production cross section for gluon fusion are calculated as well as the contributions from gluon-quark and quark-antiquark collisions to the…

High Energy Physics - Phenomenology · Physics 2011-07-19 J. H. K"uhn , E. Mirkes

Splitting amplitudes are universal functions governing the collinear behavior of scattering amplitudes for massless particles. We compute the two-loop g -> gg splitting amplitudes in QCD, N=1, and N=4 super-Yang-Mills theories, which…

High Energy Physics - Phenomenology · Physics 2010-03-25 Zvi Bern , Lance J. Dixon , David A. Kosower

We calculate the long-distance effect generated by the four-quark operators with $c$-quarks in the $B\to K^{(*)} \ell^+\ell^-$ decays. At the lepton-pair invariant masses far below the $\bar{c}c$-threshold, $q^2\ll 4m_c^2$, we use OPE near…

High Energy Physics - Phenomenology · Physics 2014-11-21 A. Khodjamirian , Th. Mannel , A. A. Pivovarov , Y. -M. Wang

We analytically compute the five-loop term in the beta function which governs the running of $\alpha_s$ --- the quark-gluon coupling constant in QCD. The new term leads to a reduction of the theory uncertainty in $\alpha_s$ taken at the…

High Energy Physics - Phenomenology · Physics 2017-03-01 P. A. Baikov , K. G. Chetyrkin , J. H. Kühn

We evaluate the quartic ghost and quark Green's functions as well as the gluon-ghost, gluon-quark and ghost-quark 4-point functions of Quantum Chromodynamics at one loop at the fully symmetric point in a linear covariant gauge. Similar…

High Energy Physics - Phenomenology · Physics 2017-03-29 J. A. Gracey

With the aim to extend the study of inclusive heavy quarkonium production at forward rapidities with the resummation of high partonic center-of-momentum-energy logarithms beyond Leading Logarithmic Approximation (LLA), the explicit analytic…

High Energy Physics - Phenomenology · Physics 2024-10-25 Maxim Nefedov

The leading short-distance contributions to hadronic hard-scattering cross sections in the operator product expansion are described by twist-two quark and gluon operators. The anomalous dimensions of these operators determine the splitting…

High Energy Physics - Phenomenology · Physics 2024-12-02 Thomas Gehrmann , Andreas von Manteuffel , Tong-Zhi Yang