|Description||2018 Fall Graduate Colloquium Series|
Observation of Higgs Boson Decay to Bottom Quarks
Despite the discovery of the Higgs boson in 2012, various theorized decay modes fitting the Standard Model have not yet been observed. Various Higgs decays that have been observed include , ZZ, WW, and . The observation of a Higgs decay mode resulting in a pair of bottom quarks (bb) is presented, where the primary contribution to the occurrence of this decay mode is an associated W or Z boson. The final states resulting from the decay mode may include 0, 1, or 2 charged leptons as well. The proton-proton data sample observed is from 2017, and consists of 41.3 fb-1 with √s = 13 TeV. Combining these results with prior data where √s = 7 TeV, 8 TeV, and 13 TeV, the significance of the observed excess number of events is found to be 4.8, with a corresponding signal strength of 1.01 ± 0.22. Further combining this with searches of this decay mode in other processes, a significance of the observed excess number of events reaches 5.6, with a corresponding signal strength of 1.04 ± 0.20.
A. M. Sirunyan et al. (CMS Collaboration), “Observation of Higgs Boson Decay to Bottom Quarks”, Phys. Rev. Lett. 121, 121801 (2018)
Md Kazi Rokunuzzaman
Multifold Emission Enhancement in Nanoimprinted Hybrid Perovskite Metasurfaces
Hybrid halide perovskites materials have distinct opto-electronic properties such as extra-long carrier diffusion lengths, strongly suppressed carrier recombination, low trapping on defects and impurities, and high carrier mobility. These unique properties are importantly to develop novel optoelectronic devices. Combining hybrid halide perovskites and metasurfaces (two-dimensional planar structures composed of meta-atoms which could alter the electromagnetic properties) could enhance the functionality (e.g. emission of light) for optoelectronic devices. In this talk, I will present a recent work on perovskite nanostructures which show significant enhancement on both linear and nonlinear photo-luminescence (up to 700 times). In addition, the stability of perovskite has been increased by large scale nanoimprint lithography and optimizing composition of perovskite thin films by alloying the organic cation.
Reference: S.V Makarov et al., “Multifold Emission Enhancement in Nanoimprinted Hybrid Perovskite Metasurfaces”, ACS Photonics 4, 728 (2017)
For more information contact: Dr. Howard Lee 254-710-2277