03 Evaluation of Run 12 L2W preview production (P12ic) TPC calibrations
Here we present some plots from the recently produced L2W stream preview production announced here. Some details of Run QA and selection can be found here.
Note: Run 12 day 85-86, have a different SC&GL calibration than the rest of the run due to changes to the ZDC which required using a different scaler for the luminosity dependence during these days. This is evaluated some below.
Fig 1 Signed DCA: In the run QA linked above you will find the slide shown below, which shows the signed DCA for primary tracks from highest positively rank vertices (average vs. runindex) for the L2 barrel and endcap W trigger separately and Q+ and Q- separately. Days 85-85 are circled in red.
Fig 2 Charge ratio: In the plots below you see distributions of tracks which satisfy our track QA cuts of nHits, etc. and tracks with pt>10 GeV are candidates for Ws. In the left panel you see the distributions for days 85-86 which show lower yield of Q- global tracks around pT~15 GeV, and then an excess of Q- tracks at high pT (Note: this is not reflected in the charge separation of the final selected W candidates in Fig 3). The right panel shows the results for the remainder of the runs, and these distributions match our expectation from previous productions (ie. Run 9 pp500).
Fig 3 Charge Separation: The Q/pT is shown for global and primary tracks for events witch satisfy our W requirements. For the left panel the charge sign separation looks very good, and sufficient for the W analysis. For days 85-86 the global track distribution looks strange, and the primary track distribution seems to be shifted towards higher Q/pT, with respect to our expectation from the other days. Additionally, I've made this plot of the charge separation for each TPC sector independently in the attachment below and plots of the sDCA for each sector attachment below.
Fig 4 Reconstructed Zs: As a cross check of the charge sign separation it is useful to look at the number of Z candidate events which have the same charge sign, as this would mean either one of the charge signs from a real Z was misreconstructed or it was a background QCD event. In both the panels below we see no Z candidates with the the same charge sign pairs.
From Jan:
This summary based on Justin's sDCA plots per sector. For the West TPC we do have sin-wave pattern of sDCA vs. sector phi - this may well be due to beam line x0,y0 being off the correct value . For the East sector 21 is clear outlier. If this gets corrected there is almost no sin-wave residua. Rather all East sectors have one common offset of sDCA.
Fig 4.
