Global analysis of fragmentation functions for pions and kaons and their uncertainties

Abstract

We present new sets of pion and kaon fragmentation functions obtained in NLO combined analyses of single-inclusive hadron production in electron-positron annihilation, proton-proton collisions, and deep-inelastic lepton-proton scattering with either pions or kaons identified in the final state. At variance with all previous fits, the present analyses take into account data where hadrons of different electrical charge are identified, which allow to discriminate quark from anti-quark fragmentation functions without the need of non trivial flavor symmetry assumptions. The resulting sets are in good agreement with all data analyzed, which cover a much wider kinematical range than in previous fits. An extensive use of the Lagrange multiplier technique is made in order to assess the uncertainties in the extraction of the fragmentation functions and the synergy from the complementary data sets in our global analysis.

Extraction of the intrinsic light-quark sea in the proton

“…From this determination of 0.8 0.2 D K Q (z, Q 2 )dz, together with Q(x, Q 2 ) from the CTEQ6L PDF [15] and D K S (z, Q 2 ) from the DSS FF [24], S(x, Q 2 ) can be readily obtained using Eq. (2).…”

“…The result of xS(x) for an evaluation using the CTEQ6L PDF [15] and the DSS FF [24] are shown in Ref. [23].…”

Transverse single-spin asymmetry and cross section forπ0andηmesons at large FeynmanxinAdamczyk1, Agakishiev2, Aggarwal3 et al. 2012Phys. Rev. D821330View full textAdd to dashboardCite

“…Also shown are the previously published STAR results for the π 0 cross-section in similar kinematic regions. The error band corresponds to the NLO pQCD theory prediction for the π 0 cross-section [32], based on the CTEQ6M5 parton distribution function [33] and the DSS fragmentation function [34]. The uncertainty for the theory prediction was obtained by increasing the factorization and renormalization scales from µ = p T to µ = 2p T .…”

Nuclear PDFs at NLO – status report and review of the EPS09 results

“…5 (left). We use the KKP fragmentation functions [30] here, but we have checked that with the newer ones, AKK08 [31] or nDSS [32,33], the results would be the same. The NLO code by Aversa et al [34] from the INCNLO [35] compilation has been utilized after changing the order of integrations to speed up the computation (see [1]).…”