Bjorn H Samset wrote: > > The checking that we have done indicates that while the cluster vertex > indeed > > finds many more vertices than the track vertex ( I guess this is what > > you mean by > > 'efficient'), > > Yes - what I meant was loosely that it finds more vertices over a wider > z-interval plus shows a narrower correlation with BB - see below. > > >in something like 25% of events (at least for run2535) > > the cluster vertex Z > > is not correlated with the BB Z. I think that this means that you > > should not only check that > > the vertex is found, but also should check that, say, BB and Cluster > > (or track, or whatever) are consistent. > > Indeed - this is on the "to-do"-list. The reason why it is not included > yet is 1) that I do not know what consistency we should demand. I don't either (yet) but I suppose a requirement that the two (or more ?) vertex Z are within N(sigma) where is N is some small integer (3?). I think that we'll also find that the TPM1 based vertexing methods will limit the number of reconstructed tracks in the FS. (I don't have the exact number in front of me, though. ) So we should not 'throw away' events because they do not have such a vertex. Conversely, I guess we never want to do tracking when we don't have 'reasonable' (and, no, I don't know exactly what 'reasonable' means in this context...at least not yet) info. from the BB large tubes. > I would be > very glad if you have done some work on this :-) And I would be very glad if I could get it written up. I was almost there, but then you had to improve the routine! > and 2) that I am working > on figuring out what goes wrong in these 25% of the events... This is way > to much to be random errors (I think), so it looks like the thing just > sometimes picks the wrong peak. Analysis of this is underways. I hope that > I will at least be able to tell _when_ something goes wrong so that the > "background" in the corr. with BB will go away. > > 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 Thanks for the quick answer! MVH, -- Ian-------------------------------------------------------------------- | I.G. Bearden | | Niels Bohr Institute Tb 3 email: bearden@nbi.dk | | Blegdamsvej 17 phone: (+45) 35 32 53 23 | | København Ø FAX: (+45) 31 42 10 16 | | Danmark | ----------------------------------------------------------------------
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