Here I explore and try to find the reason behind the data / mc discrepancy observed in my small simulation sample.

 

More details on my simulation sample can be found here.

 

The data / MC comparison plots I show on the page linked above show poor agreement. The disagreement is most pronounced in the low pt region of the pt spectra plots and the eta > 1 region of the eta spectra plots. To better understand these discrepancies I have compared a number of jet parameters between data and MC. I have also changed my trigger definitions and imposed a series of cuts to match those used by Pibero in his data / MC comparisons. By using Pibero's parameters, I can compare the data / MC agreement I see using my simulation to the agreement Pibero sees using the official 2006 jet simulation. The cuts and trigger definitions I use for the comparison of data to my simulation are:

 

• -0.7 < detEta < 1.7 (I extend my detEta cut so I can see the endcap region)
• Jet Rt < 0.94
• Sum of Jet Track Pt > 0.5
• |Vertex| < 90.0 && Vertex Rank > 0
• L2 = L2JetHigh (mono || random) && Jet Pt > 8.4
• JP = (JP1 && Jet Pt < 8.4) || (JP1 && !L2JetHigh && Jet Pt > 8.4)

 

The plots which compare data to my simulation only show jets which have an eta < 1.0 to avoid the region where data / MC comparison is poor.

 

Figure 1: Comparison of pt spectra between data and my simulation sample for the L2 trigger configuration.

 

 

Figure 2: Comparison of pt spectra between data and my simulation sample for the JP trigger configuration.

 

 

Figure 3: Comparison of eta spectra between data and my simulation sample for the L2 triggerconfiguration.

 

 

Figure 4: Comparison of eta spectra between data and my simulation sample for the JP trigger configuration.

 

Figure 5: Comparison of the phi spectra between data and my simulation sample for the L2 trigger configuration.

 

Figure 6: Comparison of the phi spectra between data and my simulation sample for the JP trigger configuration.

 

Figure 7: The Phi Vs Eta distributions of jets for data and my simulation sample for the L2 and JP trigger configurations.

 

Figure 8: Comparison of the number of tracks in a Jet between data and my simulation sample for the L2 trigger configuration.

 

Figure 9: Comparison of the number of tracks in a Jet between data and my simulation sample for the JP trigger configuration.

 

Figure 10: Comparison of the number of towers in a Jet between data and my simulation sample for the L2 trigger configuration.

 

Figure 11: Comparison of the number of towers in a Jet between data and my simulation sample for the JP trigger configuration.

 

Figure 12: Comparison of the Jet Rt between data and my simulation sample for the L2 trigger configuration.

 

Figure 13: Comparison of the Jet Rt between data and my simulation sample for the JP trigger configuration.

 

In the figures below, I compare the data to the official 2006 jet simulation. The 2006 simulation has much better statistics than my simulation. Also, Pibero has made comparisons to the 2006 simulation, so I can compare his studies to mine for consistency. I have made two changes to the cuts I use:

 

• -0.7 < eta < 0.9
• Trigger patches 4 and 11 have been disabled

 

The plots below show jets for the full eta range (-0.7 - 0.9). It appears that the data / MC agreement gets worse for eta > 0.5 for the JP trigger.

 

Figure 14: Comparison of pt spectra between data and the official 2006 simulation sample for the L2 trigger configuration.

 

Figure  15: Comparison of pt spectra between data and the official 2006 simulation sample for the JP trigger configuration.

 

 Figure 16: Comparison of eta spectra between data and the official 2006 simulation sample for the L2 trigger configuration.

 

Figure 17: Comparison of eta spectra between data and the official 2006 simulation sample for the JP trigger configuration.

 

Figure 18: Comparison of phi spectra between data and the official 2006 simulation sample for the L2 trigger configuration.

 

Figure 19: Comparison of phi spectra between data and the official 2006 simulation sample for the JP trigger configuration.

Figure 20:  The Phi Vs Eta distributions of jets for data and the official 2006 simulation sample for the L2 and JP trigger configurations.

 

Figure 21: Comparison of the number of tracks in a Jet between data and the official 2006 simulation sample for the L2 trigger configuration.

 

Figure 22: Comparison of the number of tracks in a Jet between data and the official 2006 simulation sample for the JP trigger configuration.

 

 

Figure 23: Comparison of the number of towers in a Jet between data and the official 2006 simulation sample for the L2 trigger configuration.

 

Figure 24: Comparison of the number of towers in a Jet between data and the official 2006 simulation sample for the JP trigger configuration. 

 

Figure 25: Comparison of the Jet Rt between data and the official 2006 simulation sample for the L2 trigger configuration.

 

Figure 26: Comparison of the Jet Rt between data and the official 2006 simulation sample for the JP trigger configuration.