Speaker
Description
We present the status of our all-hadronic analysis in search of pair-produced Vector-Like Quarks (VLQs) using the Boosted Event Shape Tagger (BEST) with the CMS detector using 137 $fb^{-1}$ of $\sqrt{s} = 13$ TeV proton-proton collisions at the LHC. VLQs are motivated by models which predict compositeness of the scalar Higgs boson, and which avoid increasing constraints from Higgs measurements. In the all-hadronic channel, this analysis is sensitive to all possible VLQ decay modes: T(B)->t(b)H/t(b)Z/b(t)W, capturing the highest branching fraction of each process. The high mass of the VLQs produce highly boosted objects in the final state which can be reconstructed as anti-kt R=0.8 jets and identified as either QCD/b/W/Z/H/t using the BESTagger. The tagger boosts jet constituents into various rest frames and uses neural networks to find correlations between event shape variables, such as Fox-Wolfram moments and sphericity, to determine the category of identification. We define signal regions by the classification of the highest four jets in pT. We estimate our QCD-dominant background with a data-driven 3-jet control region, then fit its normalization simultaneously with simulations of well-modeled sub-dominant background such as ttbar and W/Z+jets. The HT (scalar sum $p_T$) of the event is scanned for an excess of signal in 120 of 126 possible combinations, and the least 6 signal-rich combinations are used as validation regions for the QCD estimation. The analysis is in progress and plans to be completed soon.
| Are you are a member of the APS Division of Particles and Fields? | Yes |
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