[PAST EVENT] Christopher Thomas Johnson, Physics - Final Oral Dissertation Defense [Zoom]
Christopher Thomas Johnson, Physics - Final Oral Dissertation Defense
Zoom link is available upon request. Please email [[w|evwilk,Ellie]]
Title: “Excited J- - Resonances in Meson-Meson Scattering from Lattice QCD”
Abstract: Understanding the mass spectrum of hadrons in terms of QCD dynamics is the primary goal of hadron spectroscopy. Many hadrons appear as intermediate unstable states, or resonances, and strongly decay into lighter states. The lightest vector mesons are well determined resonances decaying into simple final states that tell a story of their quark substructure. Their excited JPC = J- - states are not as well understood decaying to many final states in energy regions (1-2 GeV) where we expect many light meson resonances. There also remain J- - resonances expected from quark models and lattice QCD calculations, that remain unobserved in experiment. I study these resonances in (1,2,3)- - from quark and gluon degrees of freedom in lattice QCD, where I extract a discrete energy spectrum in a finite sized box. This discrete spectrum has a rigorous relationship to scattering in an infinite volume, where resonances can be understood through the energy dependance of the scattering amplitude. I make use of this formalism to describe the resonances in (1,2,3)- -.
Bio: Chris Johnson was born in Towson, Maryland. He played soccer, tennis, and ran track and field at Fallston High School before graduating in 2011. He then enrolled at St. Mary's College of Maryland where he graduated with a Bachelor of Arts in physics and mathematics in 2015. He realized that he hasn't learned enough and quickly enrolled into William & Mary where his graduate studies in physics began in August 2015. In 2016-2017 he began working with his advisor Jozef Dudek in hadron spectroscopy using lattice QCD. When he is not in Small Hall he is likely not doing anything because of the pandemic... But before he liked playing soccer at the Williamsburg Indoor Sports Complex, going to the gym, and hanging out with friends. If all goes well in the thesis defense, then he will be continuing hadron spectroscopy and lattice QCD in the theory department at GSI.