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

CHAPTER 5: Estimating of the Jet Energy Scale Calibration Factor 1090.28%, for light quark and b quark jets respectively. These numbers are corrected forthe non-unity width of the pull distributions, too. Therefore, the results of bias onboth the light and the b jet energy corrections, which were quoted in Table 5.6, arere-estimated using the corrected statistical errors and summarized in Table 5.13.∆ε expl(%) ∆ε estl(%) ∆ε estl− ∆ε expl(%)-8.67±0.23(stat.)±1.2(sys.) -10.12±0.18(stat.) -1.45±0.29(stat.)±1.2(sys.)∆ε expb(%) ∆ε estb(%)∆ε estb− ∆ε expb(%)-2.08±0.36(stat.)±2.5(sys.) -1.31±0.28(stat.) 0.77±0.46(stat.)±2.5(sys.)Table 5.13: The final estimated residual jet energy corrections obtained for 100pb −1 .The corresponding expected residual corrections and the possible bias are also shown.The quoted estimated results are corrected for the non-unity width of the pull distributions.The systematical uncertainties on the expected results are mentioned sinceone cannot fit the distributions of ∆ε expl,bbetter than the quoted values which shouldbe taken into account when estimating the bias.Also in Table 5.13, the systematical uncertainty on the expected residual jet energycorrections are mentioned. Since one cannot fit the distributions of ∆ε expl,bbetter thanthe quoted uncertainties which have to be considered in the final estimation of the bias.5.6 A First Application on the 2010 Collision DataSo far, the method to estimate the residual jet energy scale calibration factors has beenintroduced and the performance of the method on simulated data has been described.In this section, the method is applied for the first time on the collision data whichis accumulated in 2010 and corresponding to 36pb −1 of proton-proton collisions at acenter of mass energy of 7 TeV. The event selection cuts are slightly different comparedto those introduced in Section 4.4, and are listed in the next section. Also in order toillustrate how well the simulated data predict the collision data, some control plots areshown in Section 5.6.2 to compare the simulated versus collision data. The simulatedsamples which are compared to the collision data, are different from what have beenused in previous sections because they need to match with the collision and detectorparameters in the low data taking period. They are listed in Table 5.14. Also thenames of 2010 collision data sets are given in the same table.The method to estimate the residual jet energy correction factors has been alreadyapplied on the simulated data and the results are obtained for 100pb −1 of integratedluminosity. Although the performance of the method was checked using a huge amountof statistics compared to the accumulated collision data, it is still interesting to inves-