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\begin{center} {\large \bf ALEPH results on quark- and gluon fragmentation} \\
   {\bf G. Rudolph,} for the ALEPH collaboration  \\  
   Inst. f. Astro- und Teilchenphysik, Universit\"at Innsbruck, Austria  \\
\end{center} 

Parton fragmentation is studied in $\epem$ annihilation into hadrons in the energy range 
91 - 207 GeV using the ALEPH detector at LEP. Scaling violation in the flavour-inclusive
$x$-distribution of charged particles has been observed which is, for $x>0.1$, 
qualitatively reproduced by global NLO parametrisations \cite{scv,QCD}. The data are better
described by the QCD-MC models. The energy variation of $<N_{ch}>$ is well explained by 
the QCD-MC models and by a two-parameter 3NLO calculation. 

Inclusive $x$ distributions of a variety of identified light mesons and baryons have been
measured at the Z pole \cite{QCD_mega,eta}. These data supplemented with $p_T$ and event 
shape distributions were used to tune the free parameters of the QCD-MC programs JETSET,
ARIADNE and HERWIG \cite{QCD_mega,CR}. The long standing discrepancy at $\pto > 1$ GeV 
can be slightly improved by using the new $p_T-$ ordered parton shower \cite{ptord}. 
The fragmentation functions of $D^{*+}$ and $B$ mesons 
as well as the relative production rates of the $0^-, \: 1^-$ and 
higher meson spin states in the c and b sector have been measured \cite{charm,bottom,B**}.
To simulate Bose-Einstein correlations in hadronic Z decays, the 
parameters $\lambda$ and $\sigma$ of the $BE_{32}$ model of PYTHIA have been determined 
\cite{BEC}. 

The gluon- and quark fragmentation functions have been measured from symmetric 3-jet 
events at two scales using b-tagging techniques \cite{xgq,gqstruct}. The failure of the 
QCD-MC models to describe the $x>0.4$ region of the gluon fragmentation function, first 
noted in \cite{gqstruct,OPAL}, is studied in 3-jet events of general topologies with high 
statistics (preliminary). The rate of neutral gluon jets with a central rapidity gap 
is found to be higher than expected from JETSET or ARIADNE \cite{CR}. The excess is 
located at low invariant mass (0.8-2.2 GeV, preliminary), as first observed by DELPHI 
\cite{DELPHI}. The colour-reconnected versions of these generators predict a much higher 
rate and thus can be excluded \cite{CR}. 
   
\begin{thebibliography}{20}
\bibitem{scv} ALEPH Collab., Phys. Lett. B 357 (1995) 487
\bibitem{QCD} ALEPH Collab., Eur. Phys. J. C 35 (2004) 457
\bibitem{QCD_mega} ALEPH Collab., Physics Reports 294 (1998) 1
\bibitem{eta} ALEPH Collab., Eur. Phys. J. C 16 (2000) 613
\bibitem{CR} ALEPH Collab., Eur. Phys. J. C 48 (2006) 685
\bibitem{ptord} T.Sj\"ostrand and P.Skands, Eur. Phys. J. C 39 (2005) 129
\bibitem{charm} ALEPH Collab., Eur. Phys. J. C 16 (2000) 597
\bibitem{bottom} ALEPH Collab., Phys. Lett. B 512 (2001) 30
\bibitem{B**} ALEPH Collab., Z. Phys. C 69 (1996) 393
\bibitem{BEC} ALEPH Collab., Phys. Lett. B 606 (2004) 265
\bibitem{xgq} ALEPH Collab., Phys. Lett. B 384 (1996) 353
\bibitem{gqstruct} ALEPH Collab., Eur. Phys. J. C 17 (2000) 1
\bibitem{OPAL} OPAL Collab., Eur. Phys. J. C 37 (2004) 25
\bibitem{DELPHI} DELPHI Collab., Phys. Lett. B 643 (2006) 147
\end{thebibliography}
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