Star-tpc-l mailing list

["Van Buren, Gene" <gene AT bnl.gov>]

Hi,

I haven't looked at an event display from the FastOffline output, but I dug through some of the Offline QA histograms that we don't show the shift crew in an effort to look for track breaking at the central membrane (which Dan reported at today's 10am meeting from the online reconstruction).

The attached plots seem to indicate that a notable fraction of global tracks start at the central membrane, but this seems to me reasonable given the pile-up tracks that must make up a large portion of the global tracks. The z of first hit on primary tracks is smooth across z=0, but for primary tracks, that z is the primary vertex position, so it's not really informative here.

Both global and primary tracks have lengths that extend beyond 300 cm (global tracks are shorter as they don't include the projection to the primary vertex). But it is a bit curious that the long primaries (300+ cm) don't seem to have a large constituency of having >45 TPC hits (it would be helpful if the plot extended further to show even longer tracks).

-Gene