Run 9 200GeV Dijet Stats & QA: Test

Here I show my proposed dijet QA plots, dijet kinematic plots, and plots showing the statistical power of the dijet measurements. I have run over ~700 runs from Pibero's DIS inclusive jet list which can be seen here.

 

I impose a number of cuts to select good dijet events:

  • valid spin4 value
  • vertex rank > 0
  • |Zvertex| < 90
  • -0.7 <= detEta <= 1.7
  • -0.8 <= eta <= 1.8
  • jet RT <= 0.94
  • jet sum track pt >= 0.5

The two highest pt jets meeting the above requirements become dijet candidates. To be counted as a dijet, one of these two jets must be geometrically matched to a jet patch which fired the L2JetHigh or JP1 triggers. In addition, the jets must be back to back in phi. The exact condition is: Cos(phi1-phi2)) <= -0.5 .

 

Figure 1 shows the statistical power of the dijet ALL measurments. I have divided the data into 9 bins each 10 GeV wide. I have also split the data into four different topologies: Barrel - Barrel, East Barrel - Endcap, West Barrel - Endcap, and Endcap - Endcap. The uncertanty in on the ALL in each bin is given by the formula below:

 


 

P_A and P_B are the polarizations of the beams, N++ is the number of dijets in that bin from events with the same helicity signs (N++ = N++ + N--), N+- is the number of dijets in a bin from events with the opposite helicity signs, R is the relative luminosity between helicity states, and the /Delta Ns are the square roots of the number of dijets of the given helicity configurations in that bin. The sum is over the number of runs. I use the relative luminosities without the bx cut as described in Joe's blog page.

 

Figure 1: Dijet ALL statistics for several dijet topologies. (Y-range selected to match projection plots).


 

 

There is no good scale which shows the size of all the error bars so the below tables give the values, along with the sigma and sqrt number of dijets in each bin.

 

Full Acceptance Errors:

Bin # 1 2 3 4 5 6 7 8 9
Delta ALL 0.00137 0.00139 0.00292 0.00664 0.01429 0.02894 0.0565 0.10022 0.16148
Sqrt # Dijets 2208.07 2192.27 1047.52 462.432 214.844 106.348 54.754 31.1448 19.5192

 

Barrel - Barrel Acceptance Errors:

Bin # 1 2 3 4 5 6 7 8 9
Delta ALL 0.00149 0.00152 0.00319 0.00714 0.01513 0.0303 0.05832 0.10495 0.16545
Sqrt # Dijets 2034.33 2009.11 961.28 430.291 202.938 101.602 53.057 29.6816 19.0526

 

 East Barrel - Endcap Acceptance Errors:

Bin # 1 2 3 4 5 6 7 8 9
Delta ALL 0.00718 0.00471 0.00861 0.01993 0.04639 0.10216 0.23463 0.36855 0.79282
Sqrt # Dijets 417.891 641.923 353.498 153.069 65.8939 30.0167 13.1909 8.6023 4.0

 

 West Barrel - Endcap Acceptance Errors:

Bin # 1 2 3 4 5 6 7 8 9
Delta ALL 0.00422 0.00505 0.01391 0.04198 0.12107 0.33145 1.02335 0.84162 2.09538
Sqrt # Dijets 712.317 600.835 218.497 72.4017 25.0599 9.2736 2.8284 3.873 1.41421

 

 Endcap - Endcap Acceptance Errors:

Bin # 1 2 3 4 5 6 7 8 9
Delta ALL 0.01277 0.02555 0.13139 0.64828 1.50888   3.27524    
Sqrt # Dijets 234.696 118.453 23.0651 4.5826 2.0 0.0 1.0 0.0 0.0

 

 

Figures 2 - 4 below show various false asymmetry plots. A pdf which defines the false asymmetries and explains how I calculate the error can be found here.

 

Figure 2: This plot sumarizes the false asymmetries. The five pannels show the five different topologies: full acceptance, barrel - barrel, east barrel - endcap, west barrel - endcap, and endcap - endcap. Each pannel displays the four false asymmetries summed over all runs and all pt bins for that particular topology.

 

 

Figure 3: Dijet AL^Y false asymetries for the 5 dijet topologies summed over all runs and divided into pt bins. Figure with zoomed in Y-axis can be found here.

 

 

Figure 4: Dijet AL^Y false asymetries for the 5 dijet topologies summed over all pt bins for each run seperately. The red line is the mean of the points and the green lines are +/- 3 sigma.

 

 

Figures 3 and 4 show two different measures of the yellow beam single spin false asymmetry. The analogous plots for the other 3 false asymmetries can be found in this pdf. In addition, I also have plots showing the size of the error bars of the false asymmetries as a function of run number. In figure 3, I show the yellow beam single spin false asymmetry summed over all runs as a function of invariant mass bin for the 5 different dijet topologies. Because of the scale, it can be hard to read off the asymmetry value and error bar size, so I have included this spreadsheet which lists the asymmetry value, number of entries, and error bar size for each bin in each topology for all four false asymmetries.

 

In addition to the asymmetry plots, I have generated some plots of dijet kinematic quantities. A pdf of all plots can be found here. Figures 5 and 6 below give two examples.

 

Figure 5: This figure shows the Pt, eta, and phi distributions of the two jets which make up dijet events.

 

Figure 6: This figure shows pt vs pt for the two jets which make up the dijet and also phi vs phi. The phi vs phi plot on the left is for dijets before the back to back condition and the plot on the right is for dijets after the back to back condition.

 

 

I have also made several QA plots. The plots show the average values of several event and dijet quantities as a function of runnumber. The red line gives the average value and the two green lines are the +/- 3sigma lines. A pdf of all QA plots can be found here.

 

Figure 7: Sample QA plot. The mean dijet mass, cosine center of momentum scattering angle, and jet pt balance are shown as a function of run index.