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RCT Calibration Status. Lindsey Gray. Previous Findings. Sucessfully fit ECAL TPG sum mean as a function of Et to a quadratic. HCAL TPG sums were scaled by some factor, causing much confusion. Found TPG(GenEt) instead of GenEt(TPG). For now, calibrating the wrong way yields better results.
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RCT Calibration Status Lindsey Gray
Previous Findings • Sucessfully fit ECAL TPG sum mean as a function of Et to a quadratic. • HCAL TPG sums were scaled by some factor, causing much confusion. • Found TPG(GenEt) instead of GenEt(TPG). • For now, calibrating the wrong way yields better results.
Current Progress • Found fitting parameters for a cubic polynomial which characterizes Generator Et as a function of H+E TPG sums in an area of .5 Delta R. • Ecal energies calibrated first, then Ecorrected + H sum is calibrated. • F(x) = Ax3+Bx2+Cx • For finding TPG Sums as a function of GenEt, a quadratic polynomial was used. • To get corrected TPG sum (corresponding Gen ET value) I solved the quadratic and took the non-negative root. • F(x) = Ax2+Bx
Results for cubic fit of GenEt(TPG_sum),Photon + Pion Problem with fit!!!
TPG Sum Distributions in problem Et range. Double Peaked
Example of Ecal Fitting Parameters • This information will be used in an RCT lookup table. • Row corresponds to Eta Bin. Which is currently segmented into Regions. • Also, implies an Et dependence for the problem on the previous slide.
Problematic Et Slices, Uncalibrated Double peaked here as well! However, peaks are inverted?
Improper Calibration Technique • I found the parameters for the function: • TPGSum = Ax^2 + Bx • This gives TPG_Corrected = A’ + B’sqrt(TPGSum) • Doesn’t vanish for TPG Sum = 0 • Found using same algorithm as proper method. • Quadratic instead of cubic polynomial. • Somehow, this gives a better result in terms of Et resolution and the means of Et resolution curves have less Et dependence.
Problematic Et Slices, again So calibrating with an improper technique gives a resolution Et dependence that we expect. Also, no Et dependence of resolution mean!
Next Steps • Figure out why the calibration failed for large Et. • Generate LUTs for the RCT based on calibration data. • Validate LUTs using QCD samples.