Here I show the data / simulation comparison where data and simulation both use the new endcap gains. I also use the detector Eta calculations which properly take into account the Endcap ...

Following the encouraging 10 run data / simu comparison (seen here) in which both data and simulation used the new endcap gains, Pibero has created a 100 run sample. This will give me enough statistics to break down the comparisons by trigger type.

There has also been a change to the way detector eta is calculated in the endcap region. Before, the calculation assumed the jet was in the barrel, now the calculation correctly handles jets which are in the endcap. The changes introduced are minor and will be discussed at the end of this page.

Figure 1: This figure shows the jet Pt for the High jet. Blue curve is data and Red curve is simulation. From left to right the pannels show events passing the L2JetHigh trigger, JP1 trigger, and events passing neither trigger. The corresponding plot for the Low pt jet is here.

Figure 2:  This figure shows the jet eta for the High jet. Blue curve is data and Red curve is simulation. From left to right the pannels show events passing the L2JetHigh trigger, JP1 trigger, and events passing neither trigger. The corresponding plot for the Low pt jet is here.

Figure 3: This figure shows the jet phi for the High jet. Blue curve is data and Red curve is simulation. From left to right the pannels show events passing the L2JetHigh trigger, JP1 trigger, and events passing neither trigger. The corresponding plot for the Low pt jet is here.

Previously, when I have shown my data / simulation comparisons for the dijet invariant mass spectra, the two jets were allowed to have any trigger. Now I am showing the mass spectra for jet pairs which have the same trigger condition. This will reduce the statistics, but will allow for a more genuine comparison given the prescaling problem described in earlier blog posts.

Figure 4: This plot shows the dijet invariant mass spectra for events where both jets come from the L2JetHigh trigger. The five pannels show the five different topology combinations: full range, barrel - barrel, east barrel - endcap, west barrel - endcap, and endcap - endcap. The plot showing the ratios can be seen here.

Figure 5: This figure is the same as figure 4 above, but now for events in which both jets pass JP1. Again, the ratio plot can be found here.

All the above plots as well as comparisons for many other quantities can be found in this pdf.

Pibero has also implemented a fix to the calculation of the detector eta of the jet. Previously, the calculation was only valid for the barrel and gave incorrect results if the jet was actually pointing at the endcap. The new detector eta calculation now correctly handles jets which point at the endcap.

Using the new detector eta calculation will have two affects: first, since I put detector eta cuts on the jets I analyze, the phase space I use will now be different. Second, jets in the endcap will now have slightly different detector eta values than they did before.

Figures 6 and 7 below show the phase spaces I use in my analysis as well as the difference in detector eta values I would get using the old incorrect calculation and the new calculation. The x-axes show the z-vertex position of a hypothetical jet and the y-axes give the physical eta. The white regions on the top and bottom are areas excluded by my detector eta cuts of -0.7 and 1.7. The z scale shows the magnitude of the difference in detector eta as given by the barrel calculation and the new endcap calculation. The black line marks a detector eta of 1, only jets in the space above this line will have a different detector etas between the two methods, the jets in the barrel had detector eta calculated correctly before. Figure 6 shows the old, incorrect phase space and figure 7 shows the correct phase space.

Figure 6: This figure shows the phase space as it was using the incorrect endcap detector eta calculation.

Figure 7: This figure shows the phase space as it is using the correct endcap detector eta calculation.

Figure 8: This figure shows where each jet in my dijet sample falls in my eta vs z-vertex phase space. The left plot is data and the right plot is simulation.

Figure 9: This figure shows the impact of the new detector eta calculation on the 1-D spectra. The blue curves are the incorrect calculation and the red curves are the new calculation. These are inclusive spectra before trigger conditions are applied.