arXiv:hep-ph/0111438·v1·High Energy Physics — Phenomenology

Unbiased gluon jet multiplicity from e $^{+}$ e $^{-}$ three-jet events

Abstract

The charged particle multiplicities of two- and three-jet events from the reaction e $^{+}$ e $^{-}$ ,\to $Z$ ^0 \to hadrons $a r e m e a s u r e df or Z$ ^0 $d ec a y s t o l i g h tq u a r k (u d s) f l a v or s, u s in g t h e d a t a s am pl eo f t h e O P A L C o l l ab or a t i o na t L E P . U s in g r ece n tt h eor e t i c a l e x p r ess i o n s t o a cco u n t f or bia ses f r o m e v e n t se l ec t i o n, r es u l t scor r es p o n d in g t o u nbia se d g l u o nj e t s a r ee x t r a c t e d . T h e u nbia se d g l u o nj e t d a t aa r eco m p a r e d t ocor r es p o n d in g r es u l t s f or q u a r k j e t s . W e d e t er min e t h er a t i o$ r \equiv \ngluon/\nq $o f m u l t i pl i c i t i es b e tw ee n g l u o nan d q u a r k j e t s a s a f u n c t i o n o f e n er g y sc a l e . W e a l so d e t er min e t h er a t i oo f s l o p es,$ r^{(1)} \equiv ({\mathrm{d}}\ngluon /{\mathrm{d}}y) /({\mathrm{d}}\nq / {\mathrm{d}}y) $, an d o f c u r v a t u r es,$ r^{(2)} \equiv ({\mathrm{d}}^2\ngluon /{\mathrm{d}}y^2) /({\mathrm{d}}^2\nq / {\mathrm{d}}y^2) $, w h er e$ y $s p ec i f i es t h ee n er g y sc a l e . A t 30 G e V, w e f in d$ r = 1.422\pm0.051 $,$ r^{(1)} = 1.761\pm0.071 $an d$ r^{(2)} = 1.98\pm0.13$, where the uncertainties are the statistical and systematic terms added in quadrature. These results are in general agreement with theoretical predictions.

Comments: comments: 5 pages, 3 figures in eps, talk given at XXXI International Symposium on Multiparticle Dynamics, Sept 1-7, 2001, Datong China. URL http://ismd31.ccnu.edu.cn/

Unbiased gluon jet multiplicity from e+e− three-jet events

Abstract

Unbiased gluon jet multiplicity from e $^{+}$ e $^{-}$ three-jet events