Study of vector meson fragmentation using a broken SU(3) model

TL;DR

This paper develops a broken SU(3) model to determine vector meson fragmentation functions, fitting data from e+e- annihilation and applying the model to proton-proton collisions at RHIC, aiding QGP studies.

Contribution

It introduces a simple SU(3) breaking model for vector meson fragmentation functions, incorporating mixing effects and fitting experimental data effectively.

Findings

Good fit to e+e- data for x > 0.01

Successful application to RHIC pp collision data

Provides baseline for QGP studies at RHIC and LHC

Abstract

Inclusive hadro production in e^+ e^- annihilation processes is examined to study the fragmentation process. A broken SU(3) model is used to determine the quark and gluon fragmentation functions of octet vector mesons, \rho and K^*, in a simple way with an SU(3) breaking parameter \lambda. These are expressed in terms of just two light quark fragmentation functions, V(x, Q2) and \gamma(x, Q2) and the gluon fragmentation function Dg(x, Q2). These functions are parameterized at the low input scale of Q0^2 = 1.5 GeV2, evolved through LO DGLAP evolution including charm and bottom flavour at appropriate thresholds, and fitted by comparison with data at the Z-pole. The model is extended with the introduction of a few additional parameters to include a study of singlet--octet mixing and hence \omega and \phi fragmentation. The model gives good fits to the available data for x >~ 0.01, where x is the scaled energy of the hadron. The model is then applied successfully to \omega, \phi production in pp collisions at the Relativistic Heavy Ion Collider, RHIC; these data form an important base-line for the study of Quark Gluon Plasma in heavy nucleus collisions at RHIC, and also in future at the LHC.