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Pythia Analysis ver 2.3: Effects of cuts

Effect of cuts on Trigger Patch ET Spectrum


Here I take a first look at how various cuts effect the trigger patch ET spectrum. For this first run, I look at 13 cuts. The first four reduce the energy range and areas of the endcap that I look in. All of these cuts are applied before any additional cuts are made. The final eleven cuts are various isolation and endcap cuts. For this analysis I used sample ppWprod from setC2 for the W sample and pt30-50 from setC4 for the QCD sampel. Details here. These figures are not scaled to 800inv_pb so all W events must be multiplied by (800/1014) and all QCD events must be multiplied by (800/12.1).


Here are the cuts:

 

  • Cut One: This cut requires that a reconstructed vertex is found, that the vertex lies in the range z=[-70,-50] and that the trigger patch ET be at least 15GeV.
  • Cut Two: This cut requires that the trigger patch ET be at least 20GeV.
  • Cut Three: This cut requires that the ET weighted average eta value of the trigger patch be less than 1.7
  • Cut Four: This cut requires that the highest energy tower be in etabin 6, 7, 8, 9, 10, or 11.
  • Cut Five: This is a cut on the ratio of the trigger patch ET to the transverse energy of all towers within a radius of 0.45 from the hightower. The cut was > 0.96 to pass.
  • Cut Six: This is a cut on the transverse distance between the point where a track crosses the endcap and the position of the high tower. The cut was set at < 0.7 to pass but this was a typo, the correct cut would have been closer to 0.07.
  • Cut Seven: This is a cut on the number of tracks above 1GeV which cross the endcap within a radius of 0.70 of the hightower. There must be 0 or 1 tracks to pass.
  • Cut Eight: This is a cut on the ratio of the energy of the seven highest U strips to the energy of all U strips under the trigger patch. The cut was > 0.7 to pass.
  • Cut Nine: This is a cut on the ratio of the energy of the two highest towers in the trigger patch to the energy of all the towers in the trigger patch. The cut was > 0.9 to pass.
  • Cut Ten: This is a cut on the number of towers with energy greater than 800MeV in the same sector as the trigger patch. The cut was < 6 to pass.
  • Cut Eleven: This is a cut on the number of hit strips in the U plane in the sector containing the trigger patch. The cut was < 48 to pass.
  • Cut Twelve: This is a cut on the ratio of the post-shower energy in the trigger patch to the full energy in the trigger patch. The cut was < 0.0005 to pass.
  • Cut Thirteen: This is a cut on the post-shower energy in the trigger patch. The cut was < 0.04 to pass.


The following plots show the effects the above cuts had on the trigger patch ET spectrum when applied in the order given.

Fig 1: This plot shows the number of events that passed a set of cuts. Bin 1 shows the raw number of events processed and each subsequent bin shows all events that passed a given cut and all cuts before it. So bin eight will show all events that passed cuts 1-7. W events are on the left and QCD events are on the right.


Fig 2: This plot shows the effects of the four phase space cuts on the trigger patch ET spectrum. Again W events are on the left and QCD events are on the right.


Fig 3: This plot shows the effects of the remaining 9 cuts on the trigger patch ET spectrum. Here the black line, instead of representing the raw spectrum, represents the ET spectrum after the four phase space cuts have been applied. Again the cuts are sequential. W events are on the left and QCD events are on the right.


Fig 4: This plot shows the effect of all thirteen cuts in an easier to see form. The black line is the raw spectrum and the red line is the spectrum after the four phase space cuts and the blue line is the spectrum after all remaining cuts. W events on the left and QCD on the right. For the W sample: In the region 20-60, the raw sample contains 4319 events, the sample after the phase space cuts contains 2400 events, and the sample after all cuts contains 1924 cuts. For the QCD sample: In the region 20-60, the raw sample contains 7022 events, the sample after the phase space cuts contains 4581 events, and the sample after all cuts contains 160 events.