Determination of alpha(s) using the next-to-leading-log approximation of QCD

A new measurement of alpha(s), is obtained from the distributions in thrust, heavy jet mass, energy-energy correlation and two recently introduced jet broadening variables following a method proposed by Catani, Trentadue, Turnock and Webber. This method includes the full calculation of O(alpha(s)2) terms and leading and next-to-leading logarithms resummed to all orders of alpha(s). The analysis is based on data taken with the DELPHI detector at LEP during 1991. I its found that the inclusion of the resummed leading and next-to-leading logarithms reduces the scale dependence of alpha(s) and allows an extension of the fit range towards the infrared limit of the kinematical range. The combined value for alpha(s) obtained at the scale mu2 = M(Z)2 is: alpha(s)(M(Z)2)= 0.123 +/- 0.006.
Bibliographic reference
DELPHI Collaboration Allen, Paul Chrin, J. T. M. Castillo Giménez, María Victoria Cortina Gil, Eduardo Ferrer Soria, Antonio Fuster Verdú, Juan A. Fez Laso, M. D. M. de Gómez Cadenas, Juan José García García, Carmen Hernández Rey, Juan José Higón Rodríguez, Emilio Lacasta Llácer, Carlos Lozano Bahilo, José Julio Martí García, Salvador Salt Cairols, José Valls Ferrer, Juan Antonio Zúñiga Román, Juan 1993 Determination of alpha(s) using the next-to-leading-log approximation of QCD Zeitschrift für Physik C-Particles and Fields 59 1 21 33