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We present two variants of an approach for evaluation of observables in analytic QCD models. The approach is motivated by the skeleton expansion in a certain class of schemes. We then evaluate the Adler function at low energies in one…

High Energy Physics - Phenomenology · Physics 2009-11-11 Gorazd Cvetic , Cristian Valenzuela

Dispersive sum rules constitute long-standing tools for extracting hadron features from QCD. We estimate the systematic uncertainties induced by assuming quark-hadron duality and improve the accuracy of the resulting predictions by…

High Energy Physics - Phenomenology · Physics 2015-03-19 Wolfgang Lucha , Dmitri Melikhov , Silvano Simula

It is usually assumed that the high-energy evolution of partons in QCD remains local in coordinate space. In particular, fixed impact-parameter scattering is thought to be in the universality class of one-dimensional reaction-diffusion…

High Energy Physics - Phenomenology · Physics 2009-01-09 S. Munier , G. P. Salam , G. Soyez

We apply the Euler transformation to accelerate the convergence of the QCD perturbative series with the aim to determine the strong coupling $\alpha_s$ in terms of the total $\tau$-decay rate $r_\tau$. The variation of the result with the…

High Energy Physics - Phenomenology · Physics 2024-01-31 K. Schilcher , C. Sebu , H. Spiesberger

Estimates of higher-order contributions for perturbative series in QCD, in view of their asymptotic nature, are delicate, though indispensable for a reliable error assessment in phenomenological applications. In this work, the Adler…

High Energy Physics - Phenomenology · Physics 2021-09-15 Matthias Jamin

We give a brief review of our recent QCD analysis carried out over the deep inelastic scattering data on F2 structure function and in the non-singlet approximation to the accuracy up to next-to-next-to-leading-order. Specifically, analysis…

High Energy Physics - Phenomenology · Physics 2010-08-05 A. V. Kotikov , V. G. Krivokhizhin , B. G. Shaikhatdenov , G. Parente

Deep inelastic scattering data on F2 structure function from various fixed-target experiments were analyzed in the non-singlet approximation with a next-to-next-to-leading-order accuracy. The study of high statistics deep inelastic…

High Energy Physics - Phenomenology · Physics 2014-11-20 B. G. Shaikhatdenov , A. V. Kotikov , V. G. Krivokhizhin , G. Parente

The leading non-perturbative contribution to the static QCD potential at r << 1/Lambda_QCD is known to be O(r^2) in operator-product expansion. It indicates that a "Coulomb+linear" potential at r <~ 1/Lambda_QCD is included in the…

High Energy Physics - Phenomenology · Physics 2007-05-23 Y. Sumino

Newer lattice results indicate that, in the Landau gauge at low spacelike momenta, the gluon propagator and the ghost dressing function are finite nonzero. This leads to a definition of the QCD running coupling, in a specific scheme, that…

High Energy Physics - Phenomenology · Physics 2019-04-02 Cesar Ayala , Gorazd Cvetic , Reinhart Kogerler

In this paper we show how an infinite system of coupled Toda-type nonlinear differential equations derived by one of us can be used efficiently to calculate the time-dependent pair-correlations in the Ising chain in a transverse field. The…

Statistical Mechanics · Physics 2015-05-13 Jacques H. H. Perk , Helen Au-Yang

We present an extension of the QCD sum rule method in the external fields so as to determine the induced pseudoscalar coupling constant g_P, which tests the validity of the partially conserved axial current (PCAC) hypothesis. This is…

Nuclear Theory · Physics 2010-04-19 E. M. Henley , W-Y. P. Hwang , L. S. Kisslinger

The Adler function D is found {\em exactly} in supersymmetric QCD. Our exact formula relates D(Q^2) to the anomalous dimension of the matter superfields \gamma (\alpha_s(Q^2)). En rout we prove another theorem: the absence of the so-called…

High Energy Physics - Theory · Physics 2015-03-05 M. Shifman , K. Stepanyantz

We derive approximate expressions for the dispersion relation of the nonlinear Klein-Gordon equation in the case of strong nonlinearities using a method based on the Linear Delta Expansion. All the results obtained in this article are fully…

Mathematical Physics · Physics 2007-05-23 P. Amore , A. Raya

We present a generalisation of our previous approach of a renormalon-motivated resummation of the QCD observables. Previously it was applied to the spacelike observables whose perturbation expansion was $D(Q^2) = a(Q^2) + O(a^2)$, where…

High Energy Physics - Phenomenology · Physics 2026-02-25 Cesar Ayala , Gorazd Cvetič , Reinhart Kögerler

We analyze the static QCD potential V_QCD(r) in the distance region 0.1 fm < r < 1 fm using perturbative QCD and OPE as basic theoretical tools. We assemble theoretical developments up to date and perform a solid and accurate analysis. The…

High Energy Physics - Phenomenology · Physics 2008-11-26 Y. Sumino

In line with some previous works, we study in this paper the meson spectrum in the framework of a second order quark-antiquark Bethe-Salpeter formalism which includes confinement. An analytic one loop running coupling constant alpha_s(Q),…

High Energy Physics - Phenomenology · Physics 2009-11-10 M. Baldicchi , G. M. Prosperi

A novel procedure for extracting hadron characteristics from QCD sum rules, based on effective continuum thresholds (necessary for the implementation of quark-hadron duality) which may depend on the involved momenta and on the Borel…

High Energy Physics - Phenomenology · Physics 2011-06-15 Wolfgang Lucha , Dmitri Melikhov , Silvano Simula

A generalization of the leading-order DGLAP evolution at small x is performed for the non-singlet structure function by resumming the leading-order DGLAP anomalous dimension to all orders in the QCD coupling. Explicit expressions are…

High Energy Physics - Phenomenology · Physics 2010-03-25 B. I. Ermolaev , M. Greco , S. I. Troyan

Using chiral Ward identities of QCD, we derive a relation for the induced pseudoscalar coupling constant which is accurate within a few percent, $g_P = 8.44 \pm 0.16$.

High Energy Physics - Phenomenology · Physics 2009-10-28 V. Bernard , N. Kaiser , Ulf-G. Meißner

This article studies a direct numerical approach for fractional advection-diffusion equations (ADEs). Using a set of cubic trigonometric B-splines as test functions, a differential quadrature (DQ) method is firstly proposed for the 1D and…

Numerical Analysis · Mathematics 2017-10-19 X. G. Zhu , Y. F. Nie , W. W. Zhang