Uncertainties in pion and kaon fragmentation functions

Abstract

We present a detailed assessment of uncertainties in parton-to-pion and parton-to-kaon fragmentation functions obtained in recent global QCD analyses of single-inclusive hadron production data at next-to-leading order accuracy. We use the robust Lagrange multiplier approach for determining uncertainties to validate the applicability of the simpler but approximate Hessian method. Extensive comparisons of the results obtained within both methods are presented for the individual partonto-pion and kaon fragmentation functions. We provide Hessian eigenvector sets of pion and kaon fragmentation functions that allow one to easily propagate their uncertainties to any observable. Various applications of these sets are presented for pion and kaon production in electron-positron annihilation, lepton-nucleon scattering, and proton-proton collisions.

Extraction of partonic transverse momentum distributions from semi-inclusive deep-inelastic scattering, Drell-Yan and Z-boson production

“…The uncertainties ∆D a h 1 are estimated from the plots in ref. [92]; they represents the only source of uncertainty in ∆m h N,theo . Statistical and systematic experimental uncertainties ∆m h N,stat and ∆m h N,sys are taken from the experimental collaborations.…”

Prospects for charged current deep-inelastic scattering off polarized nucleons at a future electron-ion collider

“…It should be also stressed that CC DIS data will lead to constraints on individual quark flavors independent of other non-perturbative inputs such as fragmentation functions (FFs). Together with W boson asymmetries from RHIC they offer invaluable checks on current estimates of flavor separated helicity PDFs [7,8] which are solely based on semi-inclusive DIS data taken at relatively low values of Q 2 where, in addition to uncertainties from FFs [47], power or higher-twist corrections can still be of some importance.…”

Charged-pion cross sections and double-helicity asymmetries in polarizedp+pcollisions ats=200 GeVAdare1, Aidala2, Ajitanand3 et al. 2015Phys. Rev. D15040View full textAdd to dashboardCite

“…The results from the three measurements are compatible. The experimental data are compared to pQCD calculations based on DSS [35,39] and AKK [37] FFs. The calculated ratio values for theory scale choices of μ ¼ p T , μ ¼ 0.5p T , and μ ¼ 2p T are also shown.…”

“…5, the charged pion cross sections are compared to pQCD calculations [54] which were performed at NLO using CTEQ6.5 unpolarized PDFs [56] and DSS [35,39] and AKK [37] FFs. In the bottom panel of each figure, the relative difference between data and theory is also shown for the DSS FFs.…”

“…Hadron production in p þ p collisions offers additional flavor sensitivity, and the Q 2 evolution of hadrons produced in e þ e − provides an additional handle on gluons. Cross section measurements of inclusive hadron production at RHIC [29][30][31][32][33][34] have already been used to help constrain FFs for charged and neutral pions and kaons, protons, and lambdas [35][36][37][38][39]. Measurements of back-to-back direct photon and charged hadron production to study hadronization in p þ p collisions at RHIC have also been performed [40].…”