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

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We present new sets of fragmentation functions in next-to-leading order QCD that are determined from e+e- annihilation data of inclusive particle production. In addition to the O(alpha_s) unpolarized cross section the longitudinal cross…

High Energy Physics - Phenomenology · Physics 2007-05-23 Janko Binnewies

This work is devoted to the study of the $\{\beta\}$-expansion of the perturbative expressions for the $e^+e^-$ annihilation Adler function $D(Q^2)$ and for the related renormalization group functions, namely for the photon vacuum…

High Energy Physics - Phenomenology · Physics 2023-12-01 A. L. Kataev , V. S. Molokoedov

We present the next-to-leading order (O(alpha_s^3)) perturbative QCD predictions for e^+e^- annihilation into four jets. A previous calculation omitted the O(alpha_s^3) terms suppressed by one or more powers of 1/N_c^2, where N_c is the…

High Energy Physics - Phenomenology · Physics 2010-11-15 L. Dixon , A. Signer

We calculate analytically the flavor non-singlet $O(\alpha_s^2)$ massive Wilson coefficients for the inclusive neutral current non-singlet structure functions $F_{1,2,L}^{ep}(x,Q^2)$ and $g_{1,2}^{ep}(x,Q^2)$ and charged current non-singlet…

High Energy Physics - Phenomenology · Physics 2016-08-24 Johannes Blümlein , Giulio Falcioni , Abilio De Freitas

Fitting $Z^0$-pole data from ALEPH and SLD, and TPC data at a lower c.m.s.\ energy, we fix the boundary condition for NLO parton$\to$hadron (hadron$=\pi^\pm, K^\pm, \sum_h h^\pm$) fragmentation functions (FFs) at the low resolution scale of…

High Energy Physics - Phenomenology · Physics 2009-10-31 S. Kretzer

We present the third-order contributions to the quark-gluon and gluon-quark timelike splitting functions for the evolution of fragmentation functions in perturbative QCD. These quantities have been derived by studying physical evolution…

High Energy Physics - Phenomenology · Physics 2015-05-28 A. A. Almasy , A. Vogt , S. Moch

We present the first genuine QCD five-loop calculation of the vacuum polarization functions: analytical terms of order alpha_s^4 n_f^2 to the absorptive parts of vector and scalar correlators. These corrections form an important…

High Energy Physics - Phenomenology · Physics 2009-11-07 P. A. Baikov , K. G. Chetyrkin , J. H. Kühn

Depending on their masses, Supersymmetric particles can affect various measurements in Z decay. Among these are the total width (or consequent extracted value of $\alpha_s$), enhancement or suppression of various flavors, and left-right and…

High Energy Physics - Phenomenology · Physics 2009-10-30 L. Clavelli , P. W. Coulter , Levan R. Surguladze

The revised version contains two additional references i.e. [13], [14] w.r.t. to the original paper. Furthermore Eq. (33) in [11] at the end of the paragraph below (3.17) must be Eq. (33) in [10]. Misprints in the list of references are…

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

We have recently calculated the second-order QCD corrections to the forward-backward asymmetry in e+e- annihilation (hep-ph/9905424). Here we recall the results and compare them to others in the literature.

High Energy Physics - Phenomenology · Physics 2007-05-23 Stefano Catani , Michael H. Seymour

The results of evaluation of mixed QED X QCD corrections to R(s) in e^+e^- annihilation and R_{\tau} in hadronic decay of the \tau lepton to O(\alpha^n\alpha_s^m), m+n \leq 3, are presented. The net effect on \alpha_s(M_Z) from the Z decay…

High Energy Physics - Phenomenology · Physics 2007-05-23 Levan R. Surguladze

Motivated by the possible large annihilation contributions implied by recent CDF and LHCb measurements on nonleptonic annihilation B meson decays, and the refined experimental measurements on hadronic B meson decays, we study the strength…

High Energy Physics - Phenomenology · Physics 2014-12-15 Qin Chang , Junfeng Sun , Yueling Yang , Xiaonan Li

We report on recent results obtained for the massive Wilson coefficients which contribute to the structure function $F_2(x,Q^2)$ at $O(\alpha_s^3)$ in the region $Q^2/m^2 \gsim 10$. In the calculation new species of harmonic sums and…

High Energy Physics - Phenomenology · Physics 2012-02-14 J. Ablinger , J. Blümlein , A. Hasselhuhn , S. Klein , C. Schneider , F. Wißbrock

We compute the perturbative component of the fragmentation function of the $b$ quark to the best of the present theoretical knowledge. The fixed-order calculation to order $\alpha_s^2$ of the fragmentation function at the initial scale is…

High Energy Physics - Phenomenology · Physics 2022-10-13 Fabio Maltoni , Giovanni Ridolfi , Maria Ubiali , Marco Zaro

We calculate the rate for $e^+e^-$ annihilation into four jets at next-to-leading order in perturbative QCD, but omitting terms that are suppressed by one or more powers of $1/\Nc^2$, where $\Nc$ is the number of colors. The…

High Energy Physics - Phenomenology · Physics 2010-11-15 A. Signer , L. Dixon

The determination of alpha_s(M_Z^2) using O(alpha_s^2) calculations of hadronic event observables in e+e- annihilation is reviewed. The large scatter among alpha_s(M_Z^2) values determined from different observables may be interpreted as…

High Energy Physics - Experiment · Physics 2007-05-23 P. N. Burrows

We use a recently completed O(alpha_s^2) fixed-order calculation of the heavy-flavour production cross section in e+e- collisions to compute the heavy-quark fragmentation function. We fit the result of our calculation, convoluted with a…

High Energy Physics - Phenomenology · Physics 2009-10-31 Paolo Nason , Carlo Oleari

We discuss the large-x behaviour of the splitting functions P_qg and P_gq and of flavour-singlet coefficient functions, such as the gluon contributions C_2,g and C_L,g to the structure functions F_2,L, in massless perturbative QCD. These…

High Energy Physics - Phenomenology · Physics 2010-12-13 A. Vogt , G. Soar , S. Moch , J. A. M. Vermaseren

We present the results of a new evaluation of the running fine structure constant $\alpha$ at the scale of the $Z$ mass in which the role of the $e^+e^-$ annihilation input data needed in this evaluation is minimized. This is achieved by…

High Energy Physics - Phenomenology · Physics 2009-10-31 S. Groote , J. G. Körner , K. Schilcher , N. F. Nasrallah

We present new sets of next-to-leading order fragmentation functions for the production of K0short and Lambda particles from the gluon and from each of the quarks, obtained by fitting to all relevant data sets from e+e- annihilation. The…

High Energy Physics - Phenomenology · Physics 2009-09-29 S. Albino , B. A. Kniehl , G. Kramer