Dynamical parton distributions revisited

Abstract

Dynamical parton densities, generated radiatively from valence-like inputs at some low resolution scale, are confronted with recent small-x data on deep inelastic and other hard scattering processes. It is shown that within theoretical uncertainties our previous (1994) dynamical/radiative parton distributions are compatible with most recent data and still applicable within the restricted accuracy margins of the presently available next-to-leading order calculations. Due to recent high precision measurements we also present an updated, more accurate, version of our (valence-like) dynamical input distributions. Furthermore, our perturbatively stable parameter-free dynamical predictions are extended to the extremely small-x region, 10 −8 < ∼ x < ∼ 10 −5 , relevant to questions concerning ultra-high-energy cosmic ray and neutrino astronomy.

Production of associated Y and open charm hadrons in pp collisions at s = 7 $$ \sqrt{s}=7 $$ and 8 TeV via double parton scattering

“…[35][36][37] are used along with the collinear approximation [26] with the leading-order gluon density taken from ref. [76]. The transverse momentum and rapidity distributions of Υ(1S) mesons also agree well with SPS predictions based on k T -factorization, while the shape of the transverse momentum spectra of Υ mesons disfavours the SPS predictions obtained using the collinear approximation.…”

“…The uncertainty reflects the variation of scale and the difference with results obtained using the collinear approximation with the gluon density from ref. [76]. Combining the estimates from eqs.…”

Exclusive photoproduction of a γ ρ pair with a large invariant mass

“…• For xq(x), we rely on the GRV-98 parameterization [30], as made available from the Durham database. To evaluate the uncertainty of this parameterization, we also consider a few other sets of PDFs, namely MSTW2008lo and MSTW2008nnlo [31], ABM11nnlo [32], CT10nnlo [33].…”

Open charm production in double parton scattering processes in the forward kinematics

“…where the small x intercept of the parton density λ is taken from the GRV parametrization [45] for the nucleon gluon pdf at Q 2 0 at small x. Numerically λ(0.5 GeV 2 ) ∼ 0.27, λ(1.0 GeV 2 ) ∼ 0. 31 Using Eqs.…”