Search for dark matter in the final state that contains a hadronically decayed W/Z boson and missing transverse energy
This event is part of the Preliminary Oral Exam.
The rate of Higgs boson decays into invisible particles is very low within the Standard Model, but it could be significantly enhanced in many beyond-standard-model scenarios where the Higgs boson decays into dark matter candidates. At the LHC, the Higgs boson can be produced in several channels including the gluon fusion (ggH) channel, the vector boson fusion (VBF) channel, and in associated production with a W/Z boson (VH channel). Although the VH channel has relatively smaller cross-section compared to the ggH or VBF channel, the hadronic decay signature of the W or Z boson in the VH channel can serve as a handle to reduce the QCD background contributions, making it very sensitive to the potential signal. In this talk I will introduce a search for dark matter in the final state that contains a hadronically decayed W/Z boson and missing transverse energy. A data sample of proton-proton collisions at sqrt(s)=13 TeV collected with the CMS detector at LHC in 2017 and 2018, corresponding to an integrated luminosity of 101 fb-1, is analyzed. A deep-learning based tagger is used to identify the hadronically decayed W/Z against jets from QCD radiation, with a better performance than traditional taggers of the same purpose. Multiple control regions orthogonal to the signal region are defined to estimate the leading background from a data-driven approach. This analysis is found to be sensitive to the invisible Higgs branching fraction as low as 40%.
Zoom Link for event: https://bostonu.zoom.us/j/96242128233?pwd=UHl3aWFLU2ViRFhmbXRDbWxSaG13QT09