Sets Of Fragmentation Functions Research Articles

Fragmentation functions for [formula omitted] using neural networks

We present a determination of fragmentation functions (FFs) for the octet baryon Ξ−/Ξ¯+ from data for single inclusive electron-positron annihilation. Our parametrization in this QCD analysis is provided in terms of a Neural Network (NN). We determine fragmentation functions for Ξ−/Ξ¯+ at next-to-leading order and for the first time at next-to-next-to-leading order in perturbative QCD. We discuss the improvement of higher-order QCD corrections, the quality of fit, and the comparison of our theoretical results with the fitted datasets. As an application of our new set of fragmentation functions, named SHKS22, we present predictions for Ξ−/Ξ¯+ baryon production in proton-proton collisions at the LHC experiments.

Uncertainties of parton distributions in a shower from the recombination model

Uncertainties of five shower parton distributions in jets at fixed Q2 = 100 GeV2 are investigated from three sets of fragmentation functions in the framework of a quark recombination model.

Proton-antiproton suppression in200AGeV Au-Au collisions

We discuss the measured nuclear suppression of $p+\overline{p}$ production in $200A$ GeV Au-Au collisions at the Relativistic Heavy Ion Collider (RHIC) within radiative energy loss. For the Albino-Kniehl-Kramer (AKK) set of fragmentation functions, proton production is dominated by gluons, giving rise to the expectation that the nuclear suppression for $p+\overline{p}$ should be stronger than for pions due to the stronger coupling of gluons to the quenching medium. Using a hydrodynamical description for the soft matter evolution, we show that this is indeed seen in the calculation. However, the expected suppression factors for pions and protons are sufficiently similar that a discrimination with present data is not possible. In the high ${p}_{T}$ region above 6 GeV where the contributions of hydrodynamics and recombination to hadron production are negligible, the model calculation is in good agreement with the data on $p+\overline{p}$ suppression.

QCD analysis of unpolarized and polarized Λ-baryon production in leading and next-to-leading order

We analyze experimental data for the production of Lambda baryons in e^+e^- annihilation in terms of scale dependent, QCD evolved, Lambda fragmentation functions. Apart from the vast majority of the data for which the polarization of an observed Lambda was not determined, we also consider the recent LEP measurements of the longitudinal polarization of Lambda's produced on the Z-resonance. Such data correspond to spin-dependent fragmentation functions for the Lambda. We point out that the present data are insufficient to satisfactorily fix these. We therefore suggest several different sets of fragmentation functions, all compatible with present data, and study the prospects for conceivable future semi-inclusive deep-inelastic scattering experiments to discriminate between them. We provide the complete next-to-leading order QCD framework for all the processes we consider.