We discuss different physics cases, mainly of the ALICE TPC, such as pile-up,
jets in pp and PbPb, Bottonium and Charmonium spectroscopy, and there
corresponding demands on the ALICE High Level Trigger (HLT) System. We show
that compression and filter strategies can reduce the data volume by factors of
5 to 10. By reconstructing (sub)events with the HLT, background events can be
rejected with a factor of up to 100 while keeping the signal (low cross-section
probes). Altogether the HLT improves the discussed physics capabilities of
ALICE by a factor of 5-100 in terms of statistics.Comment: 25 pages, 4 figure
