相关论文: ZEUS NLO QCD fits
The H1 and ZEUS Collaborations have performed new next-to-leading order QCD analyses to determine the parton density functions of the proton. QCD fits are performed using inclusive neutral and charged deep inelastic scattering cross…
New and previously published measurements on the deep inelastic $ep$ scattering cross section by the H1 and ZEUS collaborations are presented. The uncertainties can be significantly reduced by a model independent combination procedure,…
Deep inelastic scattering cross section measurements previously published by the H1 and ZEUS collaborations are combined. The procedure takes into account the systematic error correlations in a coherent way, leading to a significantly…
Next-to-leading order QCD analyses of the ZEUS data on deep inelastic scattering together with fixed-target data have been perfomed, from which the gluon and the quark densities of the proton and the value of the strong coupling constant,…
The H1 and ZEUS experiments are measuring diffractive interactions in ep collisions at HERA. Performing QCD fits of these data with NLO DGLAP, diffractive parton distribution functions can be calculated. These diffractive PDFs can be used…
Updated predictions are presented for high energy neutrino and antineutrino charged and neutral current cross-sections within the conventional DGLAP formalism of NLO QCD using modern PDF fits. PDF uncertainties from model assumptions and…
The DGLAP analyses of the nuclear parton distribution functions (nPDF) based on the global fits to the data are reviewed, and the results from EKS98 and HKM are compared. The usefulness of measuring hard probes in $pA$ collisions, at the…
Using recent and updated world data on polarized structure functions $g_1$ and $g_2$ we perform QCD analysis at the next-next-to-leading-order (NNLO) accuracy. We include also target mass correction and higher twist effect to get more…
We discuss the combination of NNLO standard QCD evolution and scheme-invariant analysis for unpolarized DIS structure functions data as a method to reduce the theoretical errors on the determination of $\alpha_s(M_Z^2)$ to $\sim 1$% in…
Single and double differential cross sections ds/dQ^2, ds/dx, ds/dy and d^2s/dQ^2dx of the inclusive neutral current (NC) measurement from the 98/99 e^-p and the charged current (CC) measurement from the 99/00 e^+p data sets are presented.…
We study the mixed effect of QCD and QED corrections to the evolution of parton distribution functions (PDFs). The Altarelli-Parisi splitting functions are extended to one order higher in QED, reaching ${\cal O}(\alpha \, \alpha_S^2)$…
We present recent progress towards a global determination of parton distribution functions (PDFs) at approximate N$^3$LO (aN$^3$LO) accuracy within the NNPDF framework. We construct a parametrisation of the $\mathcal{O}(\alpha_s^4)$ QCD…
The QCD coupling $\alpha_s$ is extracted from the energy evolution of the first two moments (multiplicity and mean) of the parton-to-hadron fragmentation functions at low fractional hadron momentum $z$. Comparisons of the experimental…
We have performed the NLO QCD global fit of BCDMS, NMC, H1 and ZEUS data with full account of point-to-point correlations using the Bayesian approach to the treatment of systematic errors. Parton distributions in the proton associated with…
We perform the next-to-next-leading-order (NNLO) QCD global fit of PDFs using inclusive charged-lepton and neutrino DIS data down to Q = 1 GeV. We also consider the data on neutrino-nucleon dimuon production, that allows us to disentangle…
We compute the next-to-next-to-leading order (NNLO) QCD corrections to event shape distributions and their mean values in deep inelastic lepton-nucleon scattering. The magnitude and shape of the corrections varies considerably between…
New ZEUS data are added into the NLO QCD analysis of the ZEUS-JETS PDF fit. The addition of high-$Q^2$ NC and CC $e^-p$ inclusive cross-section data improves the determination of the $u$-valence quark at high $x$. The addition of high-$Q^2$…
We discuss the influence of fixed target Drell-Yan data on the extraction of parton distribution functions at next-to-next-to-leading order (NNLO) in QCD. When used in a parton distribution fit, the Drell-Yan (DY) data constrain sea quark…
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. We fix the scale of the coupling constant, which eliminates the singular part of anomalous…
We perform a global parton fit to DIS and related data, including next-to-leading logarithmic (NLL) BFKL resummations in both the massless and massive sectors. The resummed fit improves over a standard next-to-leading order (NLO) DGLAP fit,…