Physics Colloquium: James Wells @ 1080 Physics Research Building (Smith Seminar Room)
Apr 3 @ 3:45 pm – 4:45 pm

Speaker: James Wells

Affiliation: University of Michigan

Title: The Theoretical Physics Ecosystem Behind the Higgs Boson Discovery

Abstract: A simplified history of the Higgs boson has Peter Higgs positing it in the mid-1960s followed by a long wait while experimentalists progressively turned up collider energies until it appeared as expected several decades later. However, in order for both the hypothesis and the experimental discovery to occur, a vast and complex theory ecosystem, across multiple subfields, had to thrive in the years before Higgs’s hypothesis and in the years that followed, building up to its discovery, which was not universally believed would even happen. In the process I describe how important the discovery of the Higgs boson has been to particle physics and what it means for the future. I also provide a response to Phil Anderson’s statement in Nature: “Maybe the Higgs boson [of particle physics] is fictitious!”

Nuclear Physics Seminar: Feng Yuan @ 4138 PRB
Apr 5 @ 1:30 pm – 2:30 pm

Speaker: Feng Yuan

Affiliation: Lawrence Berkeley National Laboratory

Title: Probing Transverse Momentum Broadening in Heavy Ion Collisions

Abstract: In this talk, we will discuss the dijet azimuthal de-correlation in relativistic heavy ion collisions as an important probe of the transverse momentum broadening effects in heavy ion collisions. We take into account both the soft gluon radiation in vacuum associated with the Sudakov logarithms and the jet PT-broadening effects in the QCD medium. We find that the Sudakov effects are dominant at the LHC, while the medium effects can play an important role at RHIC energies. This explains why the LHC experiments have not yet observed sizable PT-broadening effects in the measurement of dijet azimuthal correlations in heavy ion collisions. Future investigations at RHIC will provide a unique opportunity to study the PT-broadening effects and help to pin down the underlying mechanism for jet energy loss in a hot and dense medium.