Dear Deviants, I looked at the plot referenced below, and redirected to this list (which I am not sure is the best one, but I suppose most interested people will see it here). My questions to Djamel: What vertex distribution did you use? Have you checked to see that the reconstructed tracks have the right sign momentum? It looks to me like the sharp edge at 20 is from high momentum tracks which are more or less parallel with the TPC edge, while the counts to the left of the gap could be the "wrong sign" momentum which still come through T2. This is, of course, just guesswork, but maybe worth looking into. I would have waited until tomorrow and talked to Djam directly, but who knows...I might be at the hospital tomorrow morning... Best regards, Ian Hi all, I've made a quick simulation (single pion event) and used BrGeantToTpcTrackCandidate for T1 and T2. I checked the histograms and got a doubtful plot with T2 (T1 looks ok I think) : You can check the plot here: http://www.nbi.dk/~ouerdane/T2PadRow.gif The simulation was using the TPC calibration parameters from run 5609. I could check the same histogram with real data but before the tracking was done. I could not do it after since the pad information is not propagated by default. Anyway, the real data didn't show this gap on the left side. Any idea why ? I suspect it comes from brag but TPC experts should comment. Djam -- Djamel Ouerdane ------------------------------------------o | Niels Bohr Institute | Home: | | Blegdamsvej 17, DK-2100 Ø | Jagtvej 141 2D, | | Fax: +45 35 32 50 16 | DK-2200 Copenhagen N | | Tel: +45 35 32 52 69 | +45 35 86 19 74 | | http://www.nbi.dk/~ouerdane | | ouerdane@nbi.dk | o---------------------------------------------------------o
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