Speaker: Cara Giovanetti (Berkeley)
Title: A hint for new physics from primordial deuterium
Room: 3024
Host: Hsin-Chia Cheng
Abstract: The abundance of primordial deuterium formed after Big Bang Nucleosynthesis has been measured to percent-level precision. Predictions for the primordial deuterium abundance have achieved similar precision, but different teams have reported different central values, sometimes resulting in a mild (~2sigma) disagreement with measurement. I will introduce a new method to predict the primordial deuterium abundance using Gaussian Processes, which is robust against analysis choices like model selection, dataset selection, and theory prior. I will illustrate why different groups have found different results, and briefly discuss the new physics implications of these findings.
User:
High-Energy Seminars
Time:
12:30pm - 2:00pm
Description:
Speaker: Arthur Platschorre (Cornell)
Title: Higher Axions
Room: 3024
Host: John Terning
Abstract: A large fraction of the experimental efforts searching for the (QCD) axion focus on smaller-scale, time-intensive, resonant searches. These searches would greatly benefit from a precise estimate of the axion mass. In theory, the axion mass can be inferred from the observed dark matter abundance and numerical simulations point towards an axion mass (slightly) higher than currently searched for. These numerical predictions require axion models to have both high quality and a predictive cosmological history - that is - a post-inflationary scenario.
In this talk, I want to introduce the minimal requirements to obtain axions with exponentially good quality and a predictive cosmological scenario. These ingredients appear in theories where an axion coming from a higher-form gauge field mixes with the phase of a complex scalar field. We present a simple toy model on a 5-dimensional manifold with boundary. If time permits, we show how these scenarios may arise in string theory compactifications and discuss how to overcome additional complications these specific UV completions introduce.
Groundhog Day