Fake photon estimation as background of monophoton channel for dark matter search at the LHC

by Hakseong Lee (MS Candidate)

Wednesday Nov 13, 2019, 4:30 PM → 5:00 PM Asia/Seoul

119호 (제1과학관)

발표제목: Search for Dark Matter in Monophoton final state at √s = 13 TeV and the Phase-II Upgrade of CMS Detector

The Dark matter (DM) remains one of the most puzzling mysteries in fundamental physics and is one of the goals of a diverse, multi-pronged research program at the large hadron collider (LHC). Cosmological observa- tions demonstrate that around 85% of the mass of the Universe is comprised of the DM. A conventional DM signature at the LHC is one where one or more Standard Model (SM) particles, χ, are produced and detected, recoil- ing against missing transverse energy (MET), with magnitude associated with the non-interacting DM candidate. One such signature is a production of single photon and the MET, known as a Monophoton signature. 
In this thesis, we present the theoretical motivation for the Monophoton final state with different models, e.g., the model with large extra dimension (ADD model) and DM simplified model. In the final state of Monophoton from proton-proton collisions has several irreducible sources of backgrounds, which are essential to measure for a reliable result. One such background is QCD multijets from hadronic activity which mimics the photon. We also present the estimation of such fake photon as background of Monophoton signature for DM search in pp collision at sqrt(s) = 13 TeV data collected by the CMS.

Thesis Advisor: Prof. Chang-Seong Moon