Speaker
Dr.
David d'Enterria
(CERN)
Description
We present a new precise method to extract the QCD coupling constant alpha_s from the energy evolution of the moments of the parton-to-hadron fragmentation functions measured in e+e- annihilation and DIS e-p collisions. The evolution of the moments (multiplicity, peak, width, skewness) of the low momentum charged-hadron distribution in jets is computed at NMLLA+NLO accuracy and compared to the experimental data. Values of Lambda_QCD, and corresponding two-loop coupling constant at the Z resonance, are obtained in excellent numerical agreement with the current world average obtained using other methods at NLO accuracy. A detailed study of the (small) systematic uncertainties associated with this procedure will be also presented.
[1] R. Perez-Ramos and D. d'Enterria, "Energy evolution of the moments of the hadron distribution in QCD jets including NNLL resummation and NLO running-coupling corrections''; arXiv:1310.8534.
[2] D. d'Enterria and R. Perez-Ramos, "Determination of the strong coupling alpha_s from the energy evolution of the distributions of low momentum hadrons in QCD jets", in preparation.
Primary author
Dr.
David d'Enterria
(CERN)
Co-author
Redamy Perez-Ramos
(Jyvaskyla Univ.)
