PTCLUS: Jet-finding algorithm

The PTCLUS jet-finding algorithm is described in the note ALEPH 89 - 150 (PHYSIC 89-060) by M. Scarr and I. TenHave.

Input arguments:

ICLASS

described in 10.3.

NJLITM

maximum number of jets to search for; if NJLITM=0, the algorithm finds the number of jets using YJTLIM.

YJLITM

maximum allowed distance between two clusters (in M² / EVIS²); 0.02 is a typical value.

EVIS

visible energy. If EVIS=0, the visible energy is calculated.

Results:

NJETS

is the number of ``jets''. (-1 if algorithm fails)

TGEN

Generalized thrust

'name'

Vectors containing 4-momenta of the jets.