Vector meson fragmentation using a model with broken SU(3) at the Next-to-Leading Order

Abstract

A detailed study of fragmentation of vector mesons at the next-to-leading order (NLO) is given for e^+ e^- scattering. A model with broken SU(3) symmetry uses three input fragmentation functions \alpha(x, Q^2), \beta(x,Q^2) and \gamma(x,Q^2) and a strangeness suppression parameter \lambda to describe all the light quark fragmentation functions for the entire vector meson octet. At a starting low energy scale of Q_0^2 = 1.5 GeV^2 for three light quarks (u, d, s) along with initial parameterization, the fragmentation functions are evolved through DGLAP evolution equations at NLO and the cross-section is calculated. The heavy quarks contribution are added in appropriate thresholds during evolution. The results obtained are fitted at the momentum scale of \sqrt{s}= 91.2 GeV for LEP and SLD data. Good-quality fits are obtained for \rho, K^*, \omega and \phi mesons, implying the consistency and efficiency of this model that explains the fragmentation functions of vector mesons both at the leading and the next to leading order in QCD. Keywords: vector meson, fragmentation, SU(3) symmetry, NLO .