Kyungwook Nam

This work proposes a neutrino mass model that is derived using the minimal seesaw mechanism, which contains only two right-handed neutrinos, under the non-Abelian discrete flavor symmetry ${\mathbb{S}}_{4}\ensuremath{\bigotimes}{\mathbb{Z}}_{2}$. Two standard model doublets, ${L}_{\ensuremath{\mu}}$ and ${L}_{\ensuremath{\tau}}$, are assigned simultaneously to a $\mathbf{2}$ representation of ${\mathbb{S}}_{4}$. When the scalar fields introduced in this model, in addition to the standard model Higgs, and the leptons are coupled within the symmetry, the seesaw mechanism results in the tribimaximal neutrino mixing. This study examined the possible deviations from tribimaximal mixing related to the experimental data.

IDEA (Innovative Detector for Electron–positron Accelerators) is a detector concept designed for a future leptonic collider operating as a Higgs factory. It is based on innovative detector technologies developed over years of R&D. In September 2018, prototypes of the proposed sub-detectors have been tested for the first time on a beam line at CERN. The preliminary results from this test of a full slice of the IDEA detector and standalone measurements of dual read-out calorimeter prototypes are presented.

In this paper, a compact and easy to fabricate branch-line couplers, which can be used for tight and weak couplings with high directivity, is proposed. For these purpose, various artificial transmission lines (ATLs) are incorporated. Design of 3 dB and 10 dB couplers are designed and their characteristics are measured. Good electrical performance and circuit miniaturization indicate the validity of the present theory

Searches for heavy scalar resonances decaying to $Z\gamma$ and $\gamma\gamma$ are presented. These searches are based on the data collected with the CMS detector at 13 TeV. The search strategy is to look for an excess above the non-resonant Standard Model background in the $Z\gamma$ and $\gamma\gamma$ invariant mass spectra. The background is extracted directly from data and compared with the signal expected to be produced by hypothetical scalar resonances.

A search for a heavy resonance decaying to Zγ, with the Z boson further decaying to pairs of electrons or muons is presented.The search strategy is to look for an excess above the nonresonant Standard Model background on the + -γ invariant mass spectrum.The search is based on 13 TeV proton-proton collision data collected with the CMS detector, corresponding to the integrated luminosity of 12.9 fb -1 .

Many new physics models, e.g., compositeness, see-saw, and extra dimensions models, are expected to manifest themselves in the final states with leptons and photons. This talk presents searches for new nonresonant phenomena in the final states that include leptons and photons, focusing on the recent results obtained using data collected at Run-II of the LHC.

A search for $Z\gamma$ resonances using leptonic and hadronic final states is presented. The analysis is based on data from proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb$^{-1}$, and collected with the CMS detector at the LHC in 2016. The search strategy is to look for an excess above the nonresonant Standard Model background on the $Z\gamma$ invariant mass spectrum. Leptonic and hadronic decay modes of the $Z$ boson are investigated and the results are combined and interpreted in terms of upper limits on the product of the production cross section and the branching fraction to $Z\gamma.$