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Related papers: Low x double $ln^2(1/x)$ resummation effects at th…

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Phenomenological parameterizations of proton and neutron polarized structure functions, g1p and g1n, are developed for x > 0.02 using deep inelastic data up to ~ 50 (GeV/c)**2 as well as available experimental results on photo- and…

Nuclear Theory · Physics 2017-08-23 S. Simula , M. Osipenko , G. Ricco , M. Taiuti

We review our previous studies of truncated Mellin moments of parton distributions. We show in detail the derivation of the evolution equation for double truncated moments. The obtained splitting function has the same rescaled form as in a…

High Energy Physics - Phenomenology · Physics 2011-06-21 D. Kotlorz , A. Kotlorz

The impact of the resummed next-to-leading logarithmic small-$x$ contributions to the anomalous dimension $\gamma_{gg}$ is evaluated for the unpolarized parton densities and structure functions of the nucleon. These new terms diminish the…

High Energy Physics - Phenomenology · Physics 2016-09-06 J. Blümlein , A. Vogt

In this thesis we consider the polarized deep inelastic scattering in the region of low values of Bjorken variable, $x$. We formulate the evolution equations for the unintegrated parton distributions which include a complete resummation of…

High Energy Physics - Phenomenology · Physics 2007-05-23 B. Ziaja

We review the theory of polarized structure functions measured in deep-inelastic lepton-nucleon scattering, focusing on the most recent developments. We concentrate on the structure function $g_1$, emphasizing the phenomenological problems…

High Energy Physics - Phenomenology · Physics 2009-09-25 Stefano Forte

The impact of the resummation of leading small-$x$ terms in the anomalous dimensions is briefly summarized for the evolution of non--singlet and singlet polarized structure functions.

High Energy Physics - Phenomenology · Physics 2007-05-23 J. Blümlein , A. Vogt

The small $x$ behavior of the flavor non-singlet $g_{1}$ structure function is analysed numerically by taking into account the all-order resummation of $\alpha_{s} \ln^{2}x $ terms. We include a part of the next-to-leading logarithmic…

High Energy Physics - Phenomenology · Physics 2007-05-23 Yuichiro Kiyo , Jiro Kodaira , Hiroshi Tochimura

We discuss the quantitative consequences of the resummation of the small-x contributions to the anomalous dimensions beyond next-to-leading order in alpha_s and up to next order in ln(1/x) (NLx) in a framework based on the renormalization…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. Blümlein , V. Ravindran , W. L. van Neerven , A. Vogt

We investigate the one-gluon-exchange ($\alpha \alpha_s$) corrections to the polarized real photon structure function $g_1^\gamma(x,Q^2)$ in the massive parton model. We employ a technique based on the Cutkosky rules and the reduction of…

High Energy Physics - Phenomenology · Physics 2015-05-30 Norihisa Watanabe , Yuichiro Kiyo , Ken Sasaki

A survey is given of recent developments on the resummed small-$x$ evolution, in a framework based on the renormalization group equation, of non--singlet and singlet structure functions in both unpolarized and polarized deep--inelastic…

High Energy Physics - Phenomenology · Physics 2015-06-25 J. Blümlein , S. Riemersma , A. Vogt

A systematic study is performed of the impact of the various resummed small-$x$ contributions to the anomalous dimensions and coefficient functions on the evolution of unpolarized structure functions in deep-inelastic scattering. The proton…

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

We shown the general approach for Q2 evolution of parton densities and fragmentation functions at low x based on the diagonalization. The diagonalization leads to the two components in the Q2 evolution, each of which contains a…

High Energy Physics - Phenomenology · Physics 2015-02-26 Anatoly Kotikov

The Standard Approach (SA) for description of the structure function g_1 combines the DGLAP evolution equations and Standard Fits for the initial parton densities. The DGLAP equations describe the region of large Q^2 and large x, so there…

High Energy Physics - Phenomenology · Physics 2007-07-13 B. I. Ermolaev , M. Greco , S. I. Troyan

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 study the $Q^2$ variation of the first moment of the nucleon's spin-dependent structure function $G_1$. As $Q^2 \rightarrow 0$ the moment is determined by the low energy theorem for Compton scattering. In the deep-inelastic region the…

High Energy Physics - Phenomenology · Physics 2009-10-22 Xiangdong Ji , Peter Unrau

We construct small-x evolution equations which can be used to calculate quark and anti-quark helicity TMDs and PDFs, along with the $g_1$ structure function. These evolution equations resum powers of $\alpha_s \, \ln^2 (1/x)$ in the…

High Energy Physics - Phenomenology · Physics 2016-07-15 Yuri V. Kovchegov , Daniel Pitonyak , Matthew D. Sievert

We present calculations of the structure functions F_2(x,Q^2) and F_L(x,Q^2), concentrating on small x. After discussing the standard expansion of the structure functions in powers of \alpha_s(Q^2) we consider a leading-order expansion in…

High Energy Physics - Phenomenology · Physics 2008-02-03 R. S. Thorne

We parametrize the small x, singlet component of the proton structure function F_2 by powers and logarithms of 1/x for discrete values of Q^2 between 0.2 and 2000 GeV^2, and compare these parametrizations by applying the criterion of…

High Energy Physics - Phenomenology · Physics 2009-10-31 P. Desgrolard , L. Jenkovszky , A. Lengyel , F. Paccanoni

In the small $Q^2$ region, the sum rule for the polarized structure function $g_2$ corresponding to the moment at $n=0$ is derived. This sum rule shows that there is a tight connection among the resonances,the elastic and the continuum in…

High Energy Physics - Phenomenology · Physics 2008-11-26 Susumu Koretune , Hirofumi Kurokawa

Nuclear effects in deep inelastic scattering at low$-x$ are phenomenologically described changing the typical dynamical and/or kinematical scales characterizing the free nucleon case. In a holographic approach, this rescaling is an…

High Energy Physics - Phenomenology · Physics 2015-06-18 L. Agozzino , P. Castorina , P. Colangelo