Events - Daily
|Tuesday, September 27|
Pheno & Vino Seminar, Rouven Essig, Stony Brook, "New Direct-Detection Probes of sub-GeV Dark Matter"
Dark matter with MeV-to-GeV masses is a theoretically and phenomenologically interesting possibility. In this talk, I will describe how direct-detection experiments can probe this largely unexplored mass range. A particularly promising possibility is that dark matter scatters off electrons, causing ionization or excitation of atoms in a detector target material, which can lead to events containing one or more electrons or photons. I will review how existing XENON10 data probes dark matter with masses as low as a few MeV, and present an improved constraint using recent XENON100 data. After reviewing the challenges for xenon-based experiments to make further progress, I will discuss how experiments with different materials could significantly improve the sensitivity. This includes upcoming experiments using semiconductors (e.g. SuperCDMS, DAMIC) as well as new dedicated experiments using scintillators and other materials. I will focus on ideas that could be realized within the next five years, but also mention other efforts. I will also present a few simple sub-GeV dark matter models, which provide concrete experimental targets, and contrast direct-detection probes with searches at colliders and fixed-target experiments.
Jadwin 303 · 4:00 p.m.– 5:30 p.m.
Math Physics Seminar, Eliran Subag, Weizmann, "Critical points and the Gibbs measure of a spherical spin glass model"
For integers N let H_N(x) be an isotropic Gaussian field on the N-dimensional unit sphere, meaning that Cov(H_N(x),H_N(y)) is a function, f_N, of the inner product of <x,y>. The spherical spin glass models of statistical mechanics are such random fields, with f_N = N f with the function independent of the dimension N. The intricate landscape of the graph of H_N(x) may be studies through its critical points and the corresponding values. Focusing on the pure p-spin models, I will review recent developments concerning the distribution of the number of critical values at a given height and the associated extremal point process. Combining these results with a local investigation of the behaviour of H_N(x) in neighborhoods around the critical points, we obtain a detailed geometric picture for the Gibbs measure at low enough temperature. The measure concentrates on spherical "bands" around the deepest critical points. The main focus of the talk will be on the structure of such states, and its consequences. The talk is based on a joint work with Ofer Zeitouni.
Jadwin 343 · 4:30 p.m.– 5:30 p.m.