sPHENIX tracking discussion

[Anthony Frawley <afrawley AT fsu.edu>]

Dear MVTX experts,

Please see the plots attached to this post to tracking software:

https://chat.sdcc.bnl.gov/sphenix/pl/nq5u9mxbqpguijpjyjqmmjhm1e

The plots are made INTT hits in one case, and in the other case from silicon seeds (no TPC matching, requiring at least 3 MVTX hits and at least 2 INTT hits). The INTT hits show the expected bunch crossing distribution, extending flat to > 400 crossings. However the crossing distribution for the silicon seeds shows a steady drop in yield over the first 120 bunch crossings, followed by a very low level after that.

 

The two plots would be explained if the MVTX raw data files do not contain clusters from larger bunch crossings. In printout from the MVTX raw data decoder I see only strobe 0. The plots are from run 53821, and seem to be typical of other runs.

Can someone please look into this? This would be a problem for the new production if true, we cannot do heavy flavor physics from these files. If it is not true, I need to understand how to tell which strobe the MVTX hits come from, to investigate why the silicon seeds are inefficient for larger bunch crossings.

Thanks

Tony