Measurement of the Jet Energy Scale in the CMS experiment ... - IIHE

96 CHAPTER 5: Estimating of the Jet Energy Scale Calibration Factorwhere the quoted uncertainties are the statistical uncertainties and correspond to thedeviation of 1σ around the minimum.The 5σ contour around the minimum of the χ 2 (∆E l , ∆E b ) is obtained and shownin Figure 5.18. There is no significant correlation between light and b jet energycalibration factors observed.1.41.31.21.1∆E b10.90.80.70.60.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4∆E lFigure 5.18: The 5σ contour around the minimum of the χ 2 (∆E l , ∆E b ). The plot isobtained for an integrated luminosity of 100pb −1 .The quoted statistical uncertainties on the estimated jet energy corrections arecalculated using a number of events corresponding to an integrated luminosity of about9400pb −1 but are rescaled to an integrated luminosity of 100pb −1 . Then the numberof simulated events are indeed more than what is expected in 100pb −1 of accumulateddata. Therefore, the statistical uncertainties are actually less than what have beenquoted. The statistical uncertainties corresponding to an integrated luminosity ofabout 9400pb −1 are evaluated and reported as the uncertainties on the estimated lightand b jet energy corrections as followsand∆ε l est = −10.12 ± 0.13%,∆ε b est = −1.31 ± 0.20%.The various sources for the systematical uncertainties on the estimated results arediscussed in the Section 5.4.2.In a study based on the simulated data, the residual jet energy corrections can bedeterminded using the Monte Carlo truth information, too. A comparison between theexpected residual corrections from Monte Carlo truth information and the estimatedresidual corrections derived from the kinematic fit procedure, can then demonstrate howwell the estimation method works. If the four-vectors of the partons can be accessedfrom the simulation information, the reconstructed jets can be matched to the partons