Thrust Distributions (V. Sorin's PhD. thesis,
D. Elvira, R. Piegaia)
The KT jet
algorithm offers several advantages with respect to the fixed cone algorithm.
First, the absence
of cone boundaries avoids out-of-cone showering losses. Second, it
can be implemented in the same way at all levels (parton level theoretical
calculation, final state particle level Monte Carlo, calorimeter
cells), therefore eliminating the split/merge ambiguity. In addition, the
algorithm is infrared safe at all orders in a perturbative QCD calculation.
Event shape measurements
like the thrust distribution are useful to test the quality of the perturbative
description of the event structure, evaluate non-perturbative
contributions to radiation patterns (low ET), and extract as
from high ET event (low sensitivity to PDFs and non-perturbative effects)
Illustration:
V.Daniel Elvira
Last
modified: Mon Aug 30 16:18:43 CDT 1999