Events at Director’s Conference Room (50A-5132) LBNL

Title: Seeing through the confinement screen: DGLAP/BFKL mixing and light-ray matching in QCDAbstract: We argue that collider observables such as hadron number flux can be matched onto a linear combination of detectors/light-ray operators in perturbative QCD. The spectrum of detectors in QCD is subtle, due to recombination between the DGLAP and BFKL trajectories. We explain how to define and renormalize these trajectories … Read More

Title: Neural Networks, Scaling Laws and Effective Field Theories Abstract: Starting from simple curve fitting problems, I will explain how modern AI works by learning a large number of features from data: wide neural networks fit data to linear combinations of many random features, and stacking layers to form deep neural networks allows the features to evolve according to data. It has been empirically observed … Read More

Title: Strings from Almost Nothing Abstract: Is string theory unique? String amplitudes famously accomplish several extraordinary mathematical feats in order to UV-complete gravity, including exhibiting an infinite tower of spinning states and dual resonance. In this talk, I will show that string amplitudes can be uniquely bootstrapped from first principles, using techniques from the modern amplitudes program and quantum field theory … Read More

Title: Astro-particle Phenomena from Dark Matter and Cosmic Rays in MHD Galaxy Formation Simulations Abstract: Over the last few decades, observations of diffuse gamma-ray emission in the Milky Way have challenged astrophysical models– in particular, the excess of GeV gamma-rays detected in the Milky Way’s galactic center. Possible explanations for this signal include annihilating or decaying dark matter, or an undetected population … Read More

Title: High Quality Alternatives to the QCD Axion Abstract:The QCD axion was proposed to solve the “strong CP problem”: the question of why we observe CP violation in the quark mixing matrix, but not in the strong interactions. An alternative solution, which requires no new light degrees of freedom, is to suppose that CP is a fundamental symmetry of the … Read More

Title: BSM Light Mediator Opportunities from On-Going SM Experiments Abstract: Light mediators are a type of well-motivated particles. Their masses and couplings can vary in different theories. In this talk, I investigate several new experiments mainly motivated by SM that are sensitive to BSM light mediators, with the example of dark photon and neutrino self-interaction mediator. We found that the … Read More

Title: Picolensing as a probe of massive compact DM statesAbstract: Compact supermassive dark-matter states act as gravitational lenses. Widely spatially separated space-based gamma-ray detectors would observe parallax of such an intervening lens with respect to cosmologically distant gamma-ray bursts (GRB). This parallax can be of order the Einstein angle of the lens, resulting in a significant differential magnification of the source as … Read More

Title: GeV dark matter in the Standard Model and beyond Abstract: Astrophysical and cosmological observations unquestionably establish the existence of dark matter and its presence around us. In this talk, I will introduce GeV-scale dark matter, whose interaction with regular matter could lead to signatures in today’s most sensitive particle detectors. I will discuss the possibility of its capture and … Read More

Title: New Physics Precisely at a Tera-Z Factory Abstract: A future run on the Z-pole producing more than 1 trillion Z bosons (Tera-Z) such as proposed at FCC-ee will have indirect sensitivity to heavy new physics up to the tens of TeV scale via higher-order loop contributions to electroweak precision observables. I discuss how new physics with the right flavor … Read More

Title: Large $n$: scattering amplitudes at large multiplicity Abstract: What happens when we scatter a large number $n$ of particles, say with $n = 10^1000$? This question is out of reach of all existing approaches to scattering amplitudes, whether directly through Feynman diagrams or recursion relations. In this talk, I will study this problem at tree-level for a simple scalar … Read More