English
Related papers

Related papers: Are Parton Distributions Positive?

200 papers

QCD motivated polarized parton distributions, evolved directly in x-space, are used to predict rates for prompt photon and Jet production at RHIC and HERA-N center of mass energies. Various scenarios for the polarized gluon distributions…

High Energy Physics - Phenomenology · Physics 2014-11-17 L. E. Gordon , G. P. Ramsey

New positivity bounds are derived for quark and gluon generalized parton distributions $H$ and $E$ in spin 1/2 hadrons.

High Energy Physics - Phenomenology · Physics 2009-11-07 P. V. Pobylitsa

We present a consistent calculation of the structure functions within a light-front constituent quark model of the nucleon. Relativistic effects and the relevance of the covariance constraints are analyzed for polarized parton…

High Energy Physics - Phenomenology · Physics 2007-05-23 P. Faccioli , F. Cano , M. Traini , V. Vento

Using QCD motivated and phenomenological considerations, we construct x- dependent polarized parton distributions, which evolve under GLAP evolution, satisfy DIS data and are within positivity constraints. Each flavor is done separately and…

High Energy Physics - Phenomenology · Physics 2014-11-17 Lionel E. Gordon , Mehrdad Goshtasbpour , Gordon P. Ramsey

We consider distributions of unpolarized (polarized) quarks in unpolarized (polarized) hadrons. Our approach is based on QCD factorization. We begin with study of Basic factorization for the parton-hadron scattering amplitudes in the…

High Energy Physics - Phenomenology · Physics 2015-06-01 B. I. Ermolaev , M. Greco , S. I. Troyan

We recall the physical features of the parton distributions in the quantum statistical approach of the nucleon. Some predictions from a next-to-leading order QCD analysis are compared to recent experimental results. We also consider their…

High Energy Physics - Phenomenology · Physics 2011-07-26 Jacques Soffer

We extend the QCD Parton Model analysis using a factorized nuclear structure model incorporating individual nucleons and pairs of correlated nucleons. Our analysis of high-energy data from lepton Deep-Inelastic Scattering, Drell-Yan and W/Z…

We present a consistent calculation of the structure functions within a light-front constituent quark model of the nucleon. Relativistic effects and the relevance of the covariance constraints are analyzed for both polarized and unpolarized…

High Energy Physics - Phenomenology · Physics 2009-10-31 P. Faccioli , M. Traini , V. Vento

We investigate parton distributions in the virtual photon target, both polarized and unpolarized, up to the next-leading order (NLO) in QCD. Parton distributions can be predicted completely up to NLO, but they are…

High Energy Physics - Phenomenology · Physics 2009-10-31 Ken Sasaki , Tsuneo Uematsu

We review the analysis of polarized structure function data using perturbative QCD at next-to-leading order. We use the most recent experimental data to obtain updated results for polarized parton distributions, first moments and the strong…

High Energy Physics - Phenomenology · Physics 2009-07-09 G. Altarelli , R. D. Ball , S. Forte , G. Ridolfi

The QCD evolution equations in Modified Leading Log Approximation for the factorial moments of the multiplicity distribution in quark and gluon jets are numerically solved with initial conditions at threshold by fully taking into account…

High Energy Physics - Phenomenology · Physics 2009-10-31 Sergio Lupia

We have used QCD and polarized deep-inelastic scattering data to construct x-dependent polarized parton distributions. These flavor dependent distributions evolve under the NLO DGLAP equations, satisfy positivity constraints and agree well…

High Energy Physics - Phenomenology · Physics 2007-05-23 Gordon P. Ramsey

We review the main results of next-to-leading order QCD analyses of polarized deep-inelastic scattering data, with special attention to the assessment of theoretical uncertainties.

High Energy Physics - Phenomenology · Physics 2009-10-31 G. Ridolfi

Generalized parton distributions at large $x$ are studied in perturbative QCD approach. As $x\to 1$ and at finite $t$, there is no $t$ dependence for the GPDs which means that the active quark is at the center of the transverse space. We…

High Energy Physics - Phenomenology · Physics 2009-11-10 Feng Yuan

Polarized parton distribution functions are determined by using world data from the longitudinally polarized deep inelastic scattering experiments. A new parametrization of the parton distribution functions is adopted by taking into account…

High Energy Physics - Phenomenology · Physics 2014-11-17 Y. Goto , N. Hayashi , M. Hirai , H. Horikawa , S. Kumano , M. Miyama , T. Morii , N. Saito , T. -A. Shibata , E. Taniguchi , T. Yamanishi

We investigate the positivity of double parton distributions with a non-trivial dependence on the parton colour. It turns out that positivity is not preserved by leading-order evolution from lower to higher scales, in contrast to the case…

High Energy Physics - Phenomenology · Physics 2021-12-08 Markus Diehl , Jonathan R. Gaunt , Peter Plossl , Paolo Pichini

We perform a global leading-order QCD fit to recent polarized structure function data in order to extract a consistent set of spin-dependent parton distributions. Assuming that there is no significant intrinsic polarization of the quark…

High Energy Physics - Phenomenology · Physics 2007-05-23 T. Gehrmann , W. J. Stirling

We present the results of our QCD analysis for polarized quark distribution and structure function $xg_1 (x,Q^2)$. We use very recently experimental data to parameterize our model. New parameterizations are derived for the quark and gluon…

High Energy Physics - Phenomenology · Physics 2009-04-22 S. Atashbar Tehrani , Ali N. Khorramian

We introduce a new family of Generalised Parton Distribution models able to fulfil by construction all the theoretical properties imposed by QCD. These models are built on standard Parton Distribution Functions and extended to off-forward…

The Fourier transform of generalized parton distribution functions at xi=0 describes the distribution of partons in the transverse plane. The physical significance of these impact parameter dependent parton distribution functions is…

High Energy Physics - Phenomenology · Physics 2011-05-05 Matthias Burkardt