Search results for "PARTON DENSITIES"
showing 4 items of 4 documents
Re-weighting at the LHC: the p–Pb data impact
2016
Abstract In this work we present selected results of a comprehensive analysis of the medium modifications in proton-lead LHC Run I data, and discuss the implications on different sets of nuclear parton densities. We find that the nuclear environment has a non-negligible relevance on the experimental results. We incorporate the information from Run I into the current nuclear densities and provide novel sets of nPDFs that will be useful for future predictions.
Confronting the impact parameter dependent JIMWLK evolution with HERA data
2018
The small-$x$ evolution of protons is determined from numerical solutions of the JIMWLK equations, starting from an initial condition at moderate $x$ for a finite size proton. The resulting dipole amplitude is used to calculate the total reduced cross section $\sigma_r$ and charm reduced cross section $\sigma_{rc}$, as well as diffractive vector meson production. We compare results to experimental data from HERA and discuss fundamental problems arising from the regime sensitive to non-perturbative physics. We emphasize that information on the gluonic content of the proton, gluon spatial distributions and correlations over wide ranges in $x$, which can in principle be constrained by our stud…
DETERMINATION OF ALPHA-S FROM THE SCALING VIOLATION IN THE FRAGMENTATION FUNCTIONS IN E+E- ANNIHILATION
1993
A determination of the hadronic fragmentation functions of the Z0 boson is presented from a study of the inclusive hadron production with the DELPHI detector at LEP. These fragmentation functions were compared with the ones at lower energies, thus covering data in a large kinematic range: 196 less-than-or-equal-to Q2 less-than-or-equal-to 8312 GeV2 and x (= p(h)/E(beam)) > 0.08. A large scaling violation was observed, which was used to extract the strong coupling constant in second order QCD: alpha(s)(M(Z)) = 0.118 +/- 0.005. The corresponding QCD scale for five quark flavours is: LAMBDA(MS)(5)BAR = 230 +/- 60 MeV.
Quark and gluon distributions and $\alpha_{s}$ from nucleon structure functions at low $x$
1993
Abstract The Q2 dependence of the structure functions F2p and F2d recently measured by the NMC is compared with the predictions of perturbative QCD at next-to-leading order. Good agreement is observed, leading to accurate determinations of the quark and gluon distributions in the range 0.008 ⩽ × ⩽ 0.5. The strong coupling constant is measured from the low x data; the result agrees with previous determinations.