QTRUTH : History of a recontructed MCarlo track:

QTRUTH is part of the QSELEP package described in the previous section. However it may be called independently, outside the context of QSELEP.

QTRUTH gives information about the ``history" of a RECONSTRUCTED MCarlo track ITK. It works on Monte Carlo hadronic events generated with JETSET (or coming from an event generator interfaced with JETSET). The information provided is aimed to the classification of candidate leptons for heavy flavour tagging, but may be useful also in many other cases.

ITK

Input argument : Alpha index of the reconstructed track

IFLA

Primary quark Flavour of the event

1=d, 2=u, 3=s, 4=c, 5=b

IPOP

Flavour of the quark from gluon splitting

4 or 5 if the chain is originating from a c or a b quark respectively, which are coming from gluon splitting

0 otherwise

ICHAIN

H.F. process originating the decay chain

• -2 b $\rightarrow$ cbar u ; cbar $\rightarrow$ X
• -1 b $\rightarrow$ u X
• 1 b $\rightarrow$ c X
• 2 b $\rightarrow$ cbar c ; cbar $\rightarrow$ X
• 3 b $\rightarrow$ c $\rightarrow$ X
• 4 c $\rightarrow$ X
• 5 fragmentation or uds
ISPLIT
End of the decay chain
• 0 lepton from H.F. hadron
• 1 K $\rightarrow$ l
• 2 pi $\rightarrow$ l
• 3 gamma $\rightarrow$ l
• 4 J/psi $\rightarrow$ l
• 5 psi' $\rightarrow$ l
• 6 pi0 $\rightarrow$ l
• 7 other $\rightarrow$ l
• 8 K
• 9 pi
• 10 other
LEPID
Track identity
• -1 unidentified
• 0 non lepton
• 1 mu
• 2 tau $\rightarrow$ mu
• 3 electron
• 4 tau $\rightarrow$ e
IBMES
Identity of the decaying b particle (if any)
• -2 "oscillated" Bs
• -1 "oscillated" Bd
• 0 b baryon or non b particle
• 1 Bd
• 2 Bs
• 3 B+