Ho again, everyone.
I had a brief discussion with Michael about the ZDCs yesterday, and we
came up with an idea on how to fix the data loss problem. (Or rather, we
realized that the cuts were artificially strict...) I reprogrammed the
rdo-module, and the new result can be seen in
www.fys.uio.no/~bjornhs/2336_50k_nsc_summary.ps
This is 50k events from run 2336, triggers 4 and 6 included, and the
counts are:
Total count Ok ZDC Ratio
Trig 4 48491 40400 83%
Trig 6 8199 6480 79%
We are back to "normal" on the counts at least :-) Now about the figure:
1) The resolution got a little bit worse. Sigma is ~4 instead of ~3.2, but
this is for all events with no centrality cut (trig 4 and 6)
2) The ZDC selection no longer deforms either the trig 4 or 6 mult
distribution
3) About the mult distr: There is no real relation here to absolute mult
other than as a tool for plotting, so the vertex problem explained by
Christian does not affect this excact figure.
4) The efficiency is ~1 for all but the lowest mult event. This IS
slightly tentative because of the mult problem, so take this lightly.
All in all, I'd say that if we're happy with sigma=4cm, then this works
well again. I have the data for more detailed testing, but because of QM
there isn't too much time right now so more about this (in a slightly more
structured form) later :-)
Ping.
------------------------------------------------
Bjorn H. Samset
Master-student in Heavy Ion physics
Mob: +47 92 05 19 98 Office: +47 22 85 77 62
Adr: Kri 2A709 Sognsveien 218 0864 Oslo
This archive was generated by hypermail 2b29 : Wed Jan 10 2001 - 09:42:50 EST