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Figure 1: This figure gives an example of the away-side vs same-side jet pts for L2 data dijets with a mass between 49 and 58 GeV . The lines show various pt balance cuts where pt balance is defined as away-side pt / same-side pt. The blue cuts are 3/1 and 1/3, the red cuts are 2/1 and 1/2, and the black cuts are those used by Tai 0.73 <= ptBalance <= 1.1.

The plots for all mass bins for L2JetHigh and JP1 triggers in data and simulation can be found below. The mass range to bin numbers are:

Bin 1: 7 - 10 GeV
Bin 2: 10 - 13 GeV
Bin 3: 13 - 16 GeV
Bin 4: 16 - 19 GeV
Bin 5: 19 - 23 GeV
Bin 6: 23 - 28 GeV
Bin 7: 28 - 34 GeV
Bin 8: 34 - 41 GeV
Bin 9: 41 - 49 GeV
Bin 10: 49 - 58 GeV
Bin 11: 58 - 69 GeV
Bin 12: 69 - 82 GeV
Bin 13: 82 - 100 GeV
Bin 14: 100 - 120 GeV

The plots for L2JetHigh Data are here.
The plots for L2JetHigh Simu are here.
The plots for JP1 Data are here.
The plots for JP1 Simu are here.

Figure 2: This figure shows the effect of the 3 pt balance cuts on the dijet mass spectra in data and simulation for L2JetHigh and JP1 triggers. The top 4 plots show data with the left plots L2JetHigh and the right plots JP1. The upper 2 plots show the spectra and the bottom two plots show the ratio of uncut / cut. Red is the least restrictive cut, blue is the second least restrictive, and green is the most restrictive cut. The bottom 4 plots are the same but show simulation.

Figure 3: This figure shows the dijet mass spectrum data simulation comparison for the least restrictive cut for L2JetHigh (upper 3 plots) and JP1 (lower 3 plots) triggers. The upper left plot shows the data / simu spectra with no pt balance cut applied, the upper right plot shows the spectra with the pt balance cut applied and the bottom plot shows the data / simu ratio for no cut (Red) and with the cut (Blue).

Figure 4: Same as figure 3 for the second least restrictive pt balance cut.

Figure 5: Same as figure 3 but for the most restrictive pt balance cut.

To better characterize the events with large jet pt imbalances, I have looked at a number of correlations for events which fail the losest pt balance cut of 0.3 and 3.0.

Figure 6: This figure shows the away-side vs same-side jet pt for all L2JetHigh events. The black lines have slopes of 1/3 and 3/1 and events falling outside these lines are investigated below.

Figure 7: This figure shows jet phi vs eta for all mass bins for events which fail the pt balance cut. The upper pannels show the high pt jet and the lower pannels show the low pt jet. The left pannels are for L2JetHigh events and the right pannels are for JP1 events. This pdf shows the plots for each mass bin.

Figure 8: Same as figure 7, but now the plots show the phi vs eta positions for all individual tracks inside the jets. This pdf shows the plots for each mass bin.

Figure 9: Same as figure 7, but now the plots show the phi vs eta positions for the track which has the highest pt in each jet. This pdf shows the plots for each mass bin.

Figure 10: Same as figure 7, but now the plots show the phi vs charge signed pt for all individual tracks inside the jets. This pdf shows the plots for each mass bin.

Figure 11: Same as figure 7, but now the plots show the fraction of the jet pt carried by the track within that jet which has the highest pt vs the pt of that jet. This pdf shows the plots for each mass bin.

Figure 12: Same as figure 7, but now the plots show the average track pt (total track pt / number of tracks) for a jet vs the pt of that jet. This pdf shows the plots for each mass bin.

Below, I look at two variables which can select events with abnormally high pt tracks. I cut on the high track pt / jet pt vs pt plot and the average track pt vs jet pt plots and then look at the pt vs pt plots for the events which pass and fail the cuts.

Figure 13: This figure shows the fraction of the jet energy carried by the track with the highest pt vs the jet pt for all events. The upper two pannels show the hi pt jet in the dijet and the lower two pannels show the low pt jet in the dijet. The left pannels show data and the right pannels show simulation. The black curve shows the position of the cut. This is for the L2JetHigh trigger only. The plots for each mass bin can be seen here.

Figure 14: Same as figure 13, but now showing the average track pt in a jet vs the pt of that jet for all dijets. The plots for each mass bin can be seen here.

Figures 13 and 14 show some example cuts which may be useful in cutting events with a large pt imbalance driven by an abnormally high pt track. The next two figures show the pt vs pt distribution in data and simulation of the events which pass and fail the above cuts.

Figure 15: This figure shows the pt of the jet with the lower pseudorapidity vs the pt of the jet with the higher pseudorapidity for all dijets. The top two pannels show the events which pass the track fraction cut shown in figure 13 in data (Left) and simulation (Right). The bottom two pannels show the events which fail the track fraction cut in data and simu. I have added the lines with slopes of 1/3 and 3 for reference. This is for all L2JetHigh events. The plots for each mass bin can be seen here.

Figure 16: Same as figure 15, but now the pt vs pt plots for events passing and failing the average track pt cut are shown. The plots for each mass bin can be seen here.

At the jet meeting on 5/7/2013, Carl wanted to see the effect of a cut on just the hight track pt. The figures below show my investigation of that idea.

Figure 17: This figure shows the pt of the highest track in a jet vs the pt of that jet for L2JetHigh events in all mass bins. The layout of the figure is the same as figures 13 and 14 with the high pt jets on top and the low pt jets on bottom, data left and simu right. The black line at a track pt of 30 indicates the cut I will apply. The plots for each mass bin can be seen here.

Figure 18: This figure shows the 1-D high pt track spectra for data (Blue) and simulation (Red) for the high pt jet (Left) and low pt jet (Right) for L2JetHigh events and all dijet mass bins. The top pannels show the spectra and the bottom pannels show the data / simu ratio. The plots for each mass bin can be seen here.

Figure 19: This figure is the same as figure 13, except now the black line shows the high pt track >=30 cut which I will test. The plots for each mass bin can be seen here.

Figure 20: This figure shows the pt of the jet with the lower pseudorapidity vs the pt of the jet with the higher pseudorapidity for all dijets. The top two pannels show the events which pass the Hi Track pt cut shown in figures 17 and 19 in data (Left) and simulation (Right). The bottom two pannels show the events which fail the Hi Track pt cut in data and simu. I have added the lines with slopes of 1/3 and 3 for reference. This is for all L2JetHigh events. The plots for each mass bin can be seen here.

Figure 21: This figure shows the data (Blue) / simu (Red) comparisons for all events (Upper Left) and for only events which passed the High Track Pt cut shown in figures 17-20 (Upper Right). The data / simu ratio is also shown in the bottom pannel, the blue curve shows the ratio with no cut applied and the red curve shows the ratio with the High Track Pt cut applied.

The cut on high pt tracks at 30 GeV seems to do a good job of isolating the tails of the pt vs pt distributions while leaving most other events untouched. However, the cut does remove some events with balanced jet pt. Moreover, these events with balanced pts are evident in the simulation. I have added a secondary pt balance condition to the high track cut to keep these events. Now if a jet has a track pt >= 30 GeV, the pt balance is calculated, if the ratio of jet pts is less than 2/3 or greater than 3/2 the event is dropped. If the event falls within that range however, the event is included in the analysis.

Figure 22: Same as figure 20, except the pt balance condition has been added to the previous high pt track cut. Now the black lines show the extent of the pt balance cut (slopes are 2/3 and 3/2) The plots for each mass bin can be seen here.