Charged-Hadron Inclusive Cross Sections and Fractions ine+e−Annihilation ats

Energy evolution of the moments of the hadron distribution in QCD jets including NNLL resummation and NLO running-coupling corrections

“…(B.6) and (B.9) of appendix B. As shown in the same appendix, the proper Taylor expansion in powers of (1/ √ Y + λ) which keeps trace of higher-order corrections and leads to: 27) where the functions f i can be again found in appendix B. The new NMLLA+NLO * correction for the kurtosis affects the distribution by making it smoother in the tails and wider in the hump region.…”

“…By fitting all the measured e + e − jet distributions in the range of collision energies √ s ≈ 2-200 GeV [7,[24][25][26][27][28][29][30][31][32][33][34][35][35][36][37][38] a value of Λ QCD can be extracted which agrees very well with that obtained from the NLO coupling constant evaluated at the Z resonance, α s (m 2 Z ), in the minimal subtraction (MS) factorisation scheme [39][40][41]. Similar studies -at (N)MLLA+LO accuracy under different approximations, and with a more reduced experimental data-set-were done previously for various parametrizations of the input fragmentation function [42][43][44][45] but only with a relatively modest data-theory agreement, and an extracted LO value of Λ QCD with large uncertainties.…”

“…More concretely, we fit the experimental distributions to the expression: Each fit has five free parameters for the DG: maximum peak position, total multiplicity, width, skewness and kurtosis. In total, we analyse 32 data-sets from the following experiments: BES at √ s = 2-5 GeV [24]; TASSO at √ s = 14-44 GeV [25,26]; TPC at √ s = 29 GeV [27]; TOPAZ at √ s = 58 GeV [28]; ALEPH [29], L3 [30] and OPAL [7,31] at √ s = 91.2 GeV; ALEPH [32,35], DELPHI [33], OPAL [34] at √ s = 133 GeV; and ALEPH [35] and OPAL [36][37][38] in the range √ s = 161-202 GeV. The total number of points is 1019 and the systematic and statistical uncertainties of the spectra are added in quadrature.…”

“…We note that not all measurements originally corrected for feed-down contributions from weak decays of primary particles. This affects, in particular, the multiplicities measured for the TASSO [25,26], TPC [27] and OPAL [7] datasets which include charged particles from K s 0 and Λ decays. The effect on the peak position (and higher HBP moments) of including secondary particles from decays is negligible (<0.5%), but increases the total charged particles yields by 8% according to experimental data and Monte Carlo simulations [46].…”

Charged hadron fragmentation functions from collider data

“…In this analysis we include all available SIA measurements from LEP (ALEPH [40], DELPHI [41, 42] and OPAL [43, 44]), PETRA (TASSO [45]), PEP (TPC [46]) and SLC (SLD [47]). These measurements consist of cross sections differential in the scaling variable , where is the four-momentum of the final-state hadron, q is the four-momentum of the exchanged virtual gauge boson and .…”