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Related papers: $O(\alpha_s^2)$ Contributions to the longitudinal …

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We show that a unified approach to the perturbative evolution of structure functions which sums all logarithms of Q^2 and 1/x at leading and next-to-leading order yields results in full agreement with the 1993 HERA data for F_2. This makes…

High Energy Physics - Phenomenology · Physics 2007-05-23 R. D. Ball , S. Forte

We study the validity of a relation by Drell, Levy and Yan (DLY) connecting the deep inelastic structure (DIS) functions and the single-particle fragmentation functions in e^+e^- annihilation which are defined in the spacelike (q^2<0) and…

High Energy Physics - Phenomenology · Physics 2009-10-31 J. Blümlein , V. Ravindran , W. L. van Neerven

We present the QCD corrections of order $\alpha_s^3$ to the decay rate of $b \to u \ell \bar \nu_\ell$, with $\ell = e,\mu$, originating from diagrams with closed fermion loops and neglecting the mass of the up quark. Our calculation relies…

High Energy Physics - Phenomenology · Physics 2024-03-15 Matteo Fael , Johann Usovitsch

We present our results for the NNLL virtual corrections to the matrix elements of the operators O_1 and O_2 for the inclusive process b\to s\ell^+\ell^- in the kinematical region q^2>4m_c^2, where q^2 is the invariant mass squared of the…

High Energy Physics - Phenomenology · Physics 2009-05-20 Christoph Greub , Volker Pilipp , Christof Schüpbach

We calculate the complete $O(\alpha^2)$ initial state radiation corrections to $e^+ e^-$ annihilation into a neutral vector boson in a direct analytic computation without any approximation. The corrections are represented in terms of…

High Energy Physics - Phenomenology · Physics 2020-06-24 J. Blümlein , A. De Freitas , C. Raab , K. Schönwald

We calculate the second-order QCD corrections to the forward-backward asymmetry in $e^+e^-$ annihilation. Using the quark axis definition, we do not agree with either existing calculation, but the difference relative to one of them is small…

High Energy Physics - Phenomenology · Physics 2010-02-03 Stefano Catani , Michael H. Seymour

I present a calculation of structure functions at leading order which includes an unambiguous inclusion of the leading ln(1/x) terms for each power of alpha_s, and also the correct effects due to the mass of the charm and bottom quarks. I…

High Energy Physics - Phenomenology · Physics 2007-05-23 R. S. Thorne

We demonstrate that the angular distribution of hadrons produced in semi-inclusive deep inelastic final states is related to the inclusive longitudinal structure function. This relation could provide a new method of accessing $F_L(x,Q^2)$…

High Energy Physics - Phenomenology · Physics 2009-10-31 T. Gehrmann

We study the resummation of large logarithmic perturbative corrections to the partonic cross sections relevant for the process pp->gamma X at high transverse momentum of the photon.These corrections arise near the threshold for the partonic…

High Energy Physics - Phenomenology · Physics 2009-11-11 Daniel de Florian , Werner Vogelsang

The numerical effects of the known all-order leading and next-to-leading logarithmic small-$x$ contributions to the anomalous dimensions and coefficient functions of the unpolarized singlet evolution are discussed for the structure…

High Energy Physics - Phenomenology · Physics 2009-10-30 J. Blümlein , A. Vogt

The two-parameter Mittag-Leffler function $E_{\alpha, \beta}$ is of fundamental importance in fractional calculus. It appears frequently in the solutions of fractional differential and integral equations. Nonetheless, this vital function is…

Numerical Analysis · Mathematics 2023-12-13 Aljowhara H. Honain , Khaled M. Furati , Ibrahim O. Sarumi , Abdul Q. M. Khaliq

We present the complete twist-4 results for the semi-inclusive annihilation process $e^+ +e^- \to h+ \bar q+X$ at the tree level of perturbative quantum chromodynamics. The calculations are carried out by using the formalism obtained by…

High Energy Physics - Phenomenology · Physics 2017-09-27 Wei-hua Yang , Kai-bao Chen , Zuo-tang Liang

We discuss the order alpha_s^2 corrections to the longitudinal spin structure function g_1(x,Q^2,m^2) which are due to heavy flavour contributions. Here Q denotes the virtuality of the photon and m stands for the heavy flavour mass. Since…

High Energy Physics - Phenomenology · Physics 2007-05-23 W. L. van Neerven

Dihadron fragmentation functions and their evolution are studied in the process of $e^+e^-$ annihilation. Under the collinear factorization approximation and facilitated by the cut-vertex technique, the two hadron inclusive cross section at…

High Energy Physics - Phenomenology · Physics 2014-11-17 A. Majumder , Xin-Nian Wang

The leptonic QED radiative corrections are calculated in the next-to-leading log approximation ${\cal O}[\alpha^2 \ln(Q^2/m_e^2)]$ for unpolarized deeply inelastic $ep$--scattering in the case of mixed variables. The corrections are…

High Energy Physics - Phenomenology · Physics 2010-04-05 J. Blümlein , H. Kawamura

O(alpha^2 ln^2(m_mu/m_e)) QED corrections to the electron spectrum and angular distribution in muon decay are evaluated. Impact on the determination of Michel parameters is estimated. Current theoretical uncertainty in the muon decay…

High Energy Physics - Phenomenology · Physics 2011-03-31 Andrej Arbuzov , Andrzej Czarnecki , Andrei Gaponenko

We present calculations of structure functions using a renormalization scheme consistent expansion which is leading order in both ln(1/x) and \alpha_s(Q^2). There is no factorization scheme dependence, and the ``physical anomalous…

High Energy Physics - Phenomenology · Physics 2009-10-28 Robert S. Thorne

We will give an outline of the computation of the QCD corrections to the spin structure function g_1(x,Q^2) and the spin fragmentation function g_1^H(x,Q^2) which are measured in deep inelastic electron-proton scattering and in…

High Energy Physics - Phenomenology · Physics 2007-05-23 W. L. van Neerven

We determine the full mass and $q^2$ dependence of the heavy quark vacuum polarization function $\Pi(q^2)$ and its contribution to the total $e^+e^-$ cross section at ${\cal O}(\alpha_s^2)$ and ${\cal O}(\alpha_s^3)$ in perturbative QCD. We…

High Energy Physics - Phenomenology · Physics 2010-05-12 Andre H. Hoang , Vicent Mateu , S. Mohammad Zebarjad

We report on our calculation of the order \alpha_s^4 axial singlet contributions for the decay rates of the Z-boson as well as the vector singlet contribution to the cross section for electron-positron annihilation into hadrons. Together…

High Energy Physics - Phenomenology · Physics 2012-10-15 P. A. Baikov , K. G. Chetyrkin , J. H. Kühn , J. Rittinger