[PAST EVENT] Richard Keith Thrasher : Physics Dissertation Defense
Richard Keith Thrasher , Final Oral Examination for the Ph.D., Title: "Extensions of the Standard Model Higgs Sector."
Abstract: Theories of warped extra-dimensions have proven to be a useful framework to solve one of the most interesting puzzles left unexplained by the Standard Model ? the hierarchy problem. The hierarchy problem addresses the problem of why there is such a vast difference between the gravitational and electroweak scales. In this talk we study the custodial Randall-Sundrum model with two Higgs doublets localized on the infrared brane. In the presence of a curvature-scalar mixing, the radion which stabilizes the extra dimension now mixes with the two CP-even neutral scalars h and H. Using Higgs data collected at the LHC, we study the effects that mixing has on the parameter spaces of the type-I and type-II two-Higgs doublet models. LHC direct searches for heavy scalars in different decay channels can help distinguish between the radion and a heavy Higgs. The most important signatures involve the ratio of heavy scalar decays into b quark pairs to those into Z pairs, as well as the decay of the scalar (pseudoscalar) into a Z plus a pseudoscalar (scalar).
Bio: Richard Keith Thrasher has always been fascinated by the world of science but developed a strong affinity toward physics after taking his first introductory physics course in high school. He then attended James Madison University where he majored in physics and mathematics. He entered William & Mary in the Fall of 2013 and began working in the high energy theory group under the guidance of Professor Marc Sher. His work has focused on studying beyond Standard Model physics associated with the Higgs sector. Upon graduating he will be attending the Insight Data Science Fellows Program in Boston, MA where he will begin his career as a data scientist.