Trigger SF and b-tag calibration

Created by: mmarchegiani

The present PR includes the workflow used to compute the single electron trigger Scale Factors as 2D maps in (\eta_{SC}, p_T) of the electron and the updated b-tag SF calibration. The code has been tested on a 2018 UL dataset and there will be a future update including the 2017 and 2016 UL datasets.

Single electron trigger SF

The final SF maps are saved in pocket_coffea/parameters/semileptonic_triggerSF. The SF weights are now available to be included from the config file with the keyword sf_ele_trigger. Multiple variations are stored in the weight, corresponding to the statistical uncertainty on the SF and the systematic uncertainties corresponding to the pileup reweighting, the era dependence and the difference between low/high H_T events. Several tests have been performed to ensure closure after the SF application, by checking the electron observables 1D distributions before and after the application of the trigger SF, and a general improvement of data/MC agreement was observed. Additionally, the 2D map in (\phi, \eta_{SC}) of the electron was investigated before/after the application of the Scale Factor to check if the detector response is well modeled.

B-tag SF calibration

The b-tag SF calibration has been updated to account for additional background (single-top) and is computed after application of all the lepton and trigger SF. A dedicated closure test has been performed to ensure that after the application of the b-tag SF and the b-tag calibration SF the distributions are not changed in shape with respect to the distributions before application of the b-tag SF.