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The structure function of the proton has been investigated and has been found to possess the power law behaviour in conformity with the empirical fits to the experimental findings. We have estimated F$_{2}$(x, Q$^{2}$)/F$_{2}$(x,…

High Energy Physics - Phenomenology · Physics 2013-09-05 A. Bhattacharya , S. N. Banerjee , B. Chakraborti , S. Banerjee

We present an analysis of the current methods of approximate determination of the gluon density $G(x,Q^2)$ at low-$x$ from the scaling violations of the proton structure function $F_2(x,Q^2)$. The gluon density is obtained from DGLAP…

High Energy Physics - Phenomenology · Physics 2014-11-17 M. B. Gay Ducati , Victor P. B. Gonçalves

We summarise existing experimental and theoretical knowledge on the structure function $F_2$ in the region of low $Q^2$ and low $x$. The constraints on the behaviour of structure functions in the limit $Q^2=0$ are listed. Phenomenological…

High Energy Physics - Phenomenology · Physics 2009-09-25 Barbara Badelek , Jan Kwiecinski

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 discuss the interplay of low-x physics and QCD scaling violations by extending the unified approach describing inclusive structure functions and diffractive production in $\gamma* p$ interactions proposed in previous papers, to large…

High Energy Physics - Phenomenology · Physics 2013-05-29 Nestor Armesto , Alexei B. Kaidalov , Carlos A. Salgado , Konrad Tywoniuk

We describe the determination of the heavy quarks structure functions $F_{2,L}^{\mathcal{Q}\bar{\mathcal{Q}}}$ with help of the scaling properties. We observe that the structure functions for inclusive charm and bottom production exhibits…

High Energy Physics - Phenomenology · Physics 2022-11-08 G. R. Boroun

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

Measurements of the proton structure function $F_2$ for $0.6 < Q^2 < 17 {GeV}^2$ and $1.2 \times 10^{-5} < x <1.9 \times 10^{-3}$ from ZEUS 1995 shifted vertex data are presented. From ZEUS $F_2$ data the slopes $dF_2/d\ln Q^2$ at fixed $x$…

High Energy Physics - Experiment · Physics 2012-08-27 ZEUS Collaboration

We perform a global analysis of all available spin-dependent proton structure function data, covering a large range of Q^2, 1 < Q^2 < 30 GeV^2, and calculate the lowest moment of the g_1 structure function as a function of Q^2. From the Q^2…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. Osipenko , W. Melnitchouk , S. Simula , P. Bosted , V. Burkert , M. E. Christy , K. Griffioen , C. Keppel , S. E. Kuhn

We have estimated the contributions to the moments of polarized nucleon structure function $g_1(x,Q^2)$ coming from the region of the very low x ($10^{-5}<x$). Our approach uses the nucleon structure function extrapolated to the region of…

High Energy Physics - Phenomenology · Physics 2014-11-17 B. Ziaja

Measurements are reported of the proton and deuteron spin structure functions g1 at beam energies of 29.1, 16.2, and 9.7 GeV and g2 at a beam energy of 29.1 GeV. The integrals of g1 over x have been evaluated at fixed Q**2 = 3 (GeV/c)**2…

High Energy Physics - Phenomenology · Physics 2012-08-27 E143 collaboration

We discuss the phenomenological extraction of the leading $ j$-plane singularity from singlet structure functions $ F_s $ measured at small $ x. $ Using a saddle-point method we show that $ {\rm d ln} F_s /{\rm d ln}{1 \over x} $ is a…

High Energy Physics - Phenomenology · Physics 2010-03-25 H. Navelet , R. Peschanski , S. Wallon

The spin-averaged structure function of the neutron, F_2^n, is extracted from recent deuteron data, taking into account the small but significant corrections due to nuclear effects in the deuteron. At small x, the F_2D/F_2p ratio measured…

Nuclear Theory · Physics 2010-02-17 W. Melnitchouk , A. W. Thomas

It is shown that recent small-x measurements of the photon structure function F_2^{\gamma}(x,Q^2) by the LEP-OPAL collaboration are consistent with parameter-free QCD predictions at all presently accessible values of Q^2.

High Energy Physics - Phenomenology · Physics 2009-11-07 M. Gluck , E. Reya , I. Schienbein

We use the Bessel-inspired behavior of the structure function F2 at small x, obtained for a flat initial condition in the DGLAP evolution equations, with "frozen" and analytic modifications of the strong coupling constant to study precise…

High Energy Physics - Phenomenology · Physics 2015-06-12 A. V. Kotikov , B. G. Shaikhatdenov

Recent data on the proton F_2 structure function in the resonance region suggest that local quark-hadron duality works remarkably well for each of the low-lying resonances, including the elastic, to rather low values of Q^2. We derive…

High Energy Physics - Phenomenology · Physics 2014-11-17 W. Melnitchouk

We present a set of formulas to extract the ratio $F_{L}(x,Q^{2})/F_{2}(x,Q^{2})$ and $R(x,Q^{2})$ from the proton structure function parameterized in the next-to-next-to-leading order of the perturbative theory at low $x$ values. The…

High Energy Physics - Phenomenology · Physics 2020-06-29 B. Rezaei , G. R. Boroun

Explicit expressions for the singlet g_1 at small x and small Q^2 are obtained with the total resummation of the leading logarithmic contributions. It is shown that g_1 practically does not depend on Q^2 in this kinematic region. In…

High Energy Physics - Phenomenology · Physics 2008-11-26 B. I. Ermolaev , M. Greco , S. I. Troyan

I present a theoretical discussion of the uncertainties related to the QCD analysis of the proton structure function $F_2(x,Q^2)$ at small $x$. The role played by the `unphysical' gluon density is pointed out. It is shown how the study of…

High Energy Physics - Phenomenology · Physics 2008-11-26 Stefano Catani

The proton spin dependent structure function $g_1^p$ is analysed using the unified scheme incorporating both Altarelli-Parisi evolution and the double $ln^2(1/x)$ effects at low $x$. The latter are found to be very important in the region…

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