Pythia Analysis ver 3.2: Analysis of set C5 events using geant record

Analysis of all setC5 events using Geant tracks and vertices

 

In this analysis I looked at all QCD background events from setC5, which has an integrated luminosity on the order of what we expect to see in the data. I alo looked at W events from setC2 Wprod. The details of both event samples can be found here. This analysis was done using version 3.2 of my code which uses geant vertices and tracks, meaning we have perfec tracking for the cuts. All transverse energy is event ET and an energy scaling factor of 1.23 is used. All samples are scaled to LT=300 inverse pb;  note that the samples in all previous versions were scaled to 800 inverse pb.

 

Cuts:

I make 14 cuts which are described below. These cuts have been tightened slightly compared to those in version 3.1, now each cut throws away between 2-3% of the signal, except for cuts 6 and 7. For cuts 6 and 7, I have used a 2-D plot of the patch ET Vs. the cut quantity to cut harder on the low pT background. I have also included plots of quantites which we thought had potential to be used as cuts.

 

Plots of the 1-D spectra can be found here. Pages 1-11 show the cut spectra after the 3 preliminary phase space cuts have been made (spectra of the first 3 cuts are not shown). All events must pass the first three cuts to be analysed further. Pages 12-18 show cut spectra 8-14 after cuts 1-7 have been applied to them. Pages 19-29 show all the cut spectra after all cuts but their own have been applied. Pages 30 and 31 contain plots showing the ratio of U(V) strips above 0.5MeV under the trigger patch to the total number of U(V) strips under the patch. Pages 32 and 33 contain plots showing the number of U(V) strips above 0.5MeV in the sector(s) containing the trigger patch. Pages 34-37 contain the last four plots with cuts 1-7 applied and pages 38-41 contain the last four plots with all cuts applied.

 

Plots of the 2-D spectra can be found here. Pages 1-33 show the trigger patch ET Vs. the cut quantites so we can fine tune the cuts to eliminate background in particular ET ranges. Pages 1-11 show the cut spectra after the 3 phase space cuts have been made. Pages 12-22 show the cut spectra after cuts 1-7 have been applied. Pages 23-33 show the cut spectra after all cuts have  been applied. Pages 34 and 35 show the trigger patch Energy Vs. the ratio of energy in the 7 highest adjacent U(V) strips under the trigger patch to all U(V) strips under the trigger patch. Page 36 shows the trigger patch Energy Vs. the ratio of pre-shower energy in the trigger patch to all energy in the trigger patch. Pages 37-39 show the last three quantities with cuts 1-7 applied and pages 40-42 show the same quantities with all cuts applied. Pages 43 and 44 show trigger patch ET Vs. the ratio of U(V) strips above 0.5MeV under the trigger patch to the total number of U(V) strips under the patch. Pages 45 and 46 show the trigger patch ET Vs. the number of U(V) strips above 0.5MeV in the sector(s) containing the trigger patch. Pages 47-50 show the last four plots with cuts 1-7 applied and pages 51-54 show the plots with all cuts applied. Page 55 is a plot of the trigger patch energy Vs. the post shower energy. Page 56 is a plot of the energy in both the U and V strips under the trigger patch Vs. the energy in all post shower layers under the trigger patch. Page 57 is a plot of the energy in both the U and V strips under the trigger patch Vs. the energy in all 2nd pre-shower layers in the trigger patch. Page 58 is a plot of the trigger patch energy Vs. the energy in all 2nd pre-shower layer in the trigger patch. Pages 59-62 show the last four plots after cuts 1-7 have been applied and pages 63-66 show the same plots after all cuts have been applied.

 

  1. Cut 1: Require that the geant vertex be in the range [-70,-50]
  2. Cut 2: Require that the trigger patch ET>20GeV
  3. Cut 3: Require that the high tower not be in eta bin 1 or 12
  4. Cut 4: Isolation cut - Ratio of the ET in the trigger patch to the ET in an iso cone with r=0.45. Require > 0.96 to pass (1-D cut)
  5. Cut 5: Track iso cut - Number of geant charged tracks with pT>0.5GeV in an iso cone with r=0.7. Require < 4 and > 0 to pass (1-D cut)
  6. Cut 6: Awayside isolation cut - ET in a region Pi +/- 0.7 radians from the high tower in phi. (2-D cut)
  7. Cut 7: Awayside track cut - Number of geant charged tracks with pT>0.5GeV in same region as cut 6. (2-D cut)
  8. Cut 8: Track near high tower - Number of geant charged tracks with pT>5.0GeV in an iso cone with r=0.7. Require there be 1 and only 1 track to pass (1-D cut)
  9. Cut 9: Ratio of energy in two highest towers in trigger patch to energy in all towers in trigger patch. Require > 0.83 to pass (1-D cut)
  10. Cut 10: Ratio of energy in 7 highest adjacent U strips under the patch to the energy in all U strips under the patch. Require > 0.6 to pass (1-D cut)
  11. Cut 11: Ratio of energy in 7 highest adjacent V strips under the patch to the energy in all V strips under the patch. Require > 0.6 to pass (1-D cut)
  12. Cut 12: Number of hit U strips in sector containing the trigger patch. Require < 52 to pass (1-D cut)
  13. Cut 13: Number of hit V strips in sector containing the trigger patch. Require < 52 to pass (1-D cut)
  14. Cut 14: Ratio of energy in patch post-shower layer ot full energy in patch. Require < 0.001 to pass (1-D cut)

 

Specta

The plots showing the effect of the various cuts on the trigger patch ET spectrum can be hound here. Pages 1-14 show the effect that the first 3 cuts plus the individual cut has on the trigger patch ET spectrum. So, for example, page 7 shows the spectrum after cuts 1, 2, 3, and 7. Pages 15-26 show the effects that a number of cuts applied sequentially has on the spectrum. In all plots the black curve is the detected ET spectrum before any cuts have been made and the red curve is the ET spectrum after the cuts in question have been applied.

 

Fig 1: This plot shows the effects of all the cuts applied in sequence on the trigger patch ET spectrum. For the QCD sample: The raw spectrum contains 9.9E5 events in the region 20-70, the spectrum after the phase space cuts (1-3) contains 8.2E5 events, and the spectrum after all cuts contains 455 events. For the W sample: The raw spectrum contains 1742 events in the region 20-70, the spectrum after the phase space cuts contains 1405 events and the spectrum after all cuts contains 1120 events.

 

 

Fig 2: This plot shows the final trigger patch ET spectra after all cuts have been applied. The QCD background is in black and the W signal is in red.