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

Abstract

The moments of the single inclusive momentum distribution of hadrons in QCD jets, are studied in the next-to-modified-leading-log approximation (NMLLA) including next-to-leading-order (NLO) corrections to the alpha_s strong coupling. The evolution equations are solved using a distorted Gaussian parametrisation, which successfully reproduces the spectrum of charged hadrons of jets measured in e+e- collisions. The energy dependencies of the maximum peak, multiplicity, width, kurtosis and skewness of the jet hadron distribution are computed analytically. Comparisons of all the existing jet data measured in e+e- collisions in the range sqrt(s)~2-200 GeV to the NMLLA+NLO* predictions allow one to extract a value of the QCD parameter Lambda_QCD, and associated two-loop coupling constant at the Z resonance alpha_s(m_Z^2)= 0.1195 +/- 0.0022, in excellent numerical agreement with the current world average obtained using other methods.

40 pages, 15 figures. Minor changes. Matches published version in JHEP

References in corpus (5)

• PYTHIA 6.4 Physics and Manual
• World Summary of ${\alpha }_s$ (2012)
• Resummation of small-x double logarithms in QCD: semi-inclusive electron-positron annihilation
• Average gluon and quark jet multiplicities at higher orders
• Small-x single-particle distributions in jets from the coherent branching formalism

Cited by in corpus (10)

• 50 Years of Quantum Chromodynamics
• Fragmentation Functions Beyond Fixed Order Accuracy
• Lund and Cambridge multiplicities for precision physics
• Observation of enhanced long-range elliptic anisotropies inside high-multiplicity jets in pp collisions at $\sqrt{s}$ = 13 TeV
• Observation of the dead cone effect in charm and bottom quark jets and its QCD explanation
• Scale dependence of the q and T parameters of the Tsallis distribution in the process of jet fragmentation
• Jet Mass Dependence of Fragmentation in Positron-Proton Collisions
• Determination of alpha_s at NLO*+NNLL from a global fit of the low-z parton-to-hadron fragmentation functions in e+e- and DIS collisions
• SUSY-like relation of the splitting functions in evolution of gluon and quark jet multiplicities
• Physics case for low-$\sqrt{s}$ QCD studies at FCC-ee