3l off-Z event categories division for sensitivity improvement

[ywan2]

In order to improve the sensitivity of our analysis (through diminishing 1D likelihood 2sigma confidence intervals), we want to divide up some event categories - to split 3l_offZ* channels into 3l_offZ_high* and 3l_offZ_low*. This PR is created with the following main changes:

In analysis_processor.py:

• A new mask is added called sfosz_3l_OffZ_low_mask
  • retrieved from the modules/event_selection.py script in topcoffea package.
  • puts all 3 lepton events that has arbitrary pair below 10GeV window of Z mass to be under the mask
• Under event selection for 3l, selections.add() now has double the number of offZ categories
  • with originally 4 3l_x_offZ categories to 4 offZ_low and 4 offZ_high categories.
  • offZ_low has extra mask (mentioned above) to put everything outside on_Z in the low mass region.
  • offZ_high includes the anti-mask to put what is left in the high mass region.
• For all channels under sr_cat_dict within 3l, 3l_offZ* channels are changed into 3l_offZ_high* and 3l_offZ_low*

In datacards_post_processing.py:

• The selection of datacards for the analysis has updated list categories to match with the division of 3l offZ channels.

README is also updated with necessary instructions.

It is important to know that this PR is intertwined with topcoffeaPR#10, so both have to be implemented for the analysis to run.

[abasnet97]

TODO (based on Kelci's comments on November 10 meeting): Add a flag to be able to switch on/off these new categorizations instead of completely wiping off the baseline categorizations employed in Top-22-006.

[bryates]

I had some free time, so I fixed the lint error, and merged in the latest master branch updates. I think we just need the flag to turn these changes on/off for validation, then we should be good to merge.

[bryates]

TODO (based on Kelci's comments on November 10 meeting): Add a flag to be able to switch on/off these new categorizations instead of completely wiping off the baseline categorizations employed in Top-22-006.

There are a coupe of ways we could do this flag. The simplest might actually be in the datacard maker, where we just sum together the 3l off-Z low and high bins. @ywan2 you could work with @Andrew42 to figure this out. Otherwise, we could just put logic in the processor to use the old or new binning.

[bryates]

@ywan2 is get_off_Z_mask_low in your topcoffea repo, or did you move it over to topeft? https://github.com/TopEFT/topeft/actions/runs/6826768955/job/18567397360?pr=385#step:12:161