Session G02: Sakurai and Panofsky Prize

J.J. Sakurai Prize Talk: Baryogenesis

Abstract not available.   

J. J. Sakurai Prize Talk: Hierarchy of Hierarchies

Particle physicists confront at least three significant hierarchies -- three numbers which are extraordinarily small compared to typical microphysical scales, or simply small pure numbers. These are: the cosmological constant; the ratio of the weak scale to the Planck scale; and the value of the $\theta$ parameter of QCD. These hierarchy problems are themselves hierarchical in size, suggesting that their solutions might also be hierarchical. This talk will provide a framework for these issues, and explore how various proposed solutions to each might fit -- or fail to fit -- within such a hierarchical structure.   

W.K. Panofsky Prize Talk: Directional Cherenkov Calorimetry: Birth Pangs, Adolescence, & Maturity

Oracular dreams of grand-unification and cosmological theories foretold that neutrinos cannot be massless, that those elusive particles powered supernova explosions, and that protons die after 10$^{29}$ years. Indeed, the nucleons in our bones proved that they live longer than 10$^{26}$ years -- and the light in the sky proves our universe is 10$^{10}$ years old.\\ \\ Testing the early hypotheses demanded a new detector technology, optimized to search for rare interactions. It demanded fast, isochronous, single photoelectron photomultiplier tubes, N$_{2}$ calibration lasers, reverse osmosis purification of water, fast waveform digitizers…ushering in an era of massive, totally-active, Cherenkov ring-imaging calorimeters. Now the target medium, water, of the pioneering detector has morphed into ice, heavy water, seawater, and clear and scintillating oil. The sources of neutrinos in the seminal experiment - atmosphere and a supernova - have evolved to include accelerators, the sun, nuclear reactors, and cosmic rays.\\ \\ I will recall the death of the simplest unifying theories and trace the tortuous path from an atmospheric muon-neutrino deficit, to a definitive measurement of neutrino mass difference and the dream of unraveling CP violation.   

Sakurai Thesis Prize Talk: Quantum Gravity Constraints for Effective Field Theories

A fundamental open question in quantum field theory is related to ultraviolet completion: Which low-energy effective field theories can be consistently combined with quantum gravity? A celebrated example of the swampland program--the investigation of this question--is the weak gravity conjecture, which mandates, for a U(1) gauge field coupled consistently to gravity, the existence of a state with charge-to-mass ratio greater than unity. In this talk, I will discuss the tension between the weak gravity conjecture and the naturalness principle in quantum field theory, generalize the weak gravity conjecture to multiple gauge fields, and exhibit a model in which the weak gravity conjecture solves the standard model hierarchy problem. Further, this thesis demonstrates that gravitational effective field theories can be constrained by infrared physics principles alone, namely, analyticity, unitarity, and causality. I will discuss bounds related to the weak gravity conjecture that can be derived by placing such infrared constraints on higher-dimension operators in a photon-graviton effective theory. In addition, I will explore bounds on higher-curvature corrections to the Einstein equations using analyticity of graviton scattering amplitudes and unitarity of an arbitrary tree-level completion, as well as constraints on the couplings in models of massive gravity. Building on this thesis, the weak gravity conjecture can be proved using ideas in black hole entropy. Finally, I will briefly comment on the other topics of this thesis work, including a reformulation of graviton perturbation theory as well as various other results in emergent gravity, holography, and cosmology.