Calorimetry for the LC Detector
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Hi all,
there are 3 points to be kept in mind aiming for good calorimetry,
electromagnetic as well as hadronic.
(1) missing Et is very important for all kinds of new physics.
a large constant term or large non-gaussian tail will kill any
analysis.
(2) The resolution of the energy flux measurement from tracker
and E-cal is unbeatable. However, if there are overlapping
high momentum tracks in the center of a jet, the pattern
recognition program is likely to assign wrong hits to a track.
This might result in a completely wrong momentum with the
corresponding effect on the energy flux.
Excluding those events will bias the sample. An independent
calorimetric measurement can check and resolve the problem.
(3) Redundancy: there might be problems with the TPC. Take just the
Aleph accidents with easily imaginable worse or fatal ends.
Good calorimetry means:
- sig(E)/E < .5 sqrt(E/GeV) for the hadronic calorimetry
- <= 1% constant term,
- good containment: as small as possible non-gaussian tails
Of corse the last 2 points are not independent.
These conditions can only be met, if the calorimeter is sufficiently
segmented: transversly and longitudinally.
Not only a good E-cal is needed, but also a good H-cal is of
equal importance.
Peter Steffen
