.Mitchell Institute (MIST) Events
Fall 2022
Symmetries Beyond the Standard Model: Cosmology and Non-Accelerator Signatures
Speaker: Urjit A. Yajnik (Indian Institute of Technology, Bombay)Host: Doojin Kim
Neutrino physics presents a fascinating set of new phenomena yet hides some crucial evidence needed to relate these to other possibilities such as leptogenesis and lepton number violation. One generic feature of embedding the right chiral neutrino states in a gauge theory is the inevitable occurrence of Domain Walls in [...]
The Southern Stellar Stream Spectroscopic Survey: Overview and Latest Science Result
Speaker: Ting Li (University of Toronto)Host: Justin Spilker
The Southern Stellar Stream Spectroscopic Survey (S5) is an ongoing spectroscopic program that maps the newly discovered stellar streams with the fiber-fed AAOmega spectrograph on the Anglo-Australian Telescope (AAT). S5 is the first systematic program pursuing a complete census of known streams in the Southern Hemisphere, providing a uniquely powerful sample for understanding the building blocks of the Milky Way's stellar halo, the progenitors [...]
Celestial Amplitudes from Flat Space Limits of AdS/Witten Diagrams
Speaker: Ana Raclariu (Perimeter Institute)Host: Aritra Saha
The search for pragmatic observables of quantum gravity remains at the forefront of fundamental physics research. A large set of ideas collectively known as the gauge-gravity duality have proven fruitful in tackling this problem. While such a duality is believed to universally govern gravitational theories, its nature in theories of [...]Exploring the Production of High-Energy Photons with Reionization Analogue Galaxies
Speaker: Grace Olivier (Texas A&M University)Host: Justin Spilker
Currently, the observational and theoretical toolbox cannot discern between accretion onto black holes or hot massive stars as the source of ionizing photons for this cosmic reionization. The key to understanding the physical processes responsible for reionizing the universe are the nearby galaxies that are analogues to galaxies during the [...]Type IIB flux Compactifications with h^{1,1}=0
Speaker: Timm Wrase (Lehigh University)Host: Katrin Becker
I revisit type IIB flux compactifications that are mirror dual to type IIA on rigid Calabi-Yau manifolds. We found a variety of interesting new solutions, like infinite families of Minkowski vacua and infinite families of AdS_4 solutions with arbitrarily large numbers of spacetime filling D3 branes. I will discuss how [...]
Luminous Merger Between Two Star-forming Galaxies 1.7Gyr After the Big Bang
Speaker: Kate Pitchford (Texas A&M University)Host: Justin Spilker
The bulk of stellar and black hole mass buildup in galaxies occurs in the high-redshift Universe in short, intense bursts of star formation and black hole accretion. However, the exact role of these two processes in assembling galaxies, as well as how much they affect one another, remains unclear. It [...]
September 14, 2022
4:00 pm – 5:00 pm (CDT)
Searching for New Physics Using End-to-End Physics Reconstruction
Speaker: Michael Andrews (Carnegie Mellon University)Host: Doojin Kim
Growing interest in searches for exotic new physics at CMS has highlighted the need for a new generation of particle reconstruction algorithms. For many exotic physics searches, sensitivity is constrained not by the ability to extract information from particle-level data but by inefficiencies in the reconstruction of the particle-level quantities [...]Trivially-Acting Symmetries as Topological Operators
Speaker: Thomas Vandermeulen (Texas A&M University)Host: Katrin Becker
The modern view of symmetries is that they should be regarded as topological operators which act on the states of a theory. We show that this formulation can be extended to trivially-acting symmetries, which are naturally described as a mix of line and point operators. This allows us to refine [...]Early JWST Results on Distant Galaxies and the Lensed Star Earendel
Speaker: Dan Coe (Space Telescope Science Institute)Host: Justin Spilker
JWST is beginning to transform our understanding of the early universe. Over 100 papers on the arXiv have analyzed JWST data of galaxies. Some early tantalizing results have been puzzling, including claims of disks at z > 4, extremely dusty galaxies out to z > 5, impossibly massive galaxies at [...]
Heavy Axions across Frontiers: Searches at Beam Dump Facilities and X-ray/Gamma-ray Telescopes
Speaker: Soubhik Kumar (Lawrence Berkeley National Laboratory)Host: Kevin Kelly
Heavy axions can arise in the context of Grand Unified theories where a confining dark gauge group unifies with the Standard Model (SM) gauge group. Depending on the strength of the axion coupling to the SM, heavy axion lifetimes can vary drastically, requiring very different observational probes. I will discuss [...]Dynamics of Spinning Binaries From an Effective Field Theory Perspective
Speaker: Radu Roiban (Penn State University)Host: Ergin Sezgin
The general relativistic two-body dynamics is a subject of great theoretical and practical interest in light of the ongoing observations of gravitational waves by the LIGO/Virgo observatories. In recent years the classical limit of quantum scattering amplitudes provided a means to establish the state of the art in the weak-field [...]Too Big to Fail? 6D Stellar Streams in the Milky Way and Cosmological Simulations
Speaker: Nora Shipp (Massachusetts Institute of Technology)Host: Justin Spilker
Recent large photometric, astrometric, and spectroscopic surveys have enabled the first systematic observations of Milky Way stellar streams in 6D. At the same time, cutting edge cosmological simulations are now at resolutions that allow for the study of dwarf galaxy streams around Milky Way-like hosts. In this talk, I will present the [...]A New Step in Interacting Dark Sector Cosmologies for the Hubble Tension and Large Scale Structure
Speaker: Taewook Youn (University of Texas, Austin)Host: Doojin Kim
In this talk, I propose Stepped Partially Acoustic Dark Matter (SPartAcous), a new class of interacting dark sector models with a qualitatively new cosmological behavior that can simultaneously address the two most important tensions in cosmological data, the H0 and S8 tensions. The defining element of this class of models [...]A Top-Down Dictionary for Double Holography
Speaker: Andreas Karch (University of Texas)Host: Katrin Becker
Holographic interpretations of Randall-Sundrum (RS) branes provide a laboratory to explore the way quantum information evolves in field theories coupled to gravity. Despite this importance, the holographic interpretation of RS branes in terms of a theory of gravity coupled to a CFT is rather ad-hoc. In this talk, we use [...]The Connection Between Black Hole Growth and Major Galaxy Mergers
Speaker: Ezequiel Treister (The Pontifical Catholic University of Chile)Host: Justin Spilker
A clear picture is forming, directly linking the most intense SMBH growth episodes (luminous Active Galactic Nuclei, or AGN) and major galaxy mergers. In this scenario, the more traditional AGN unification paradigm in which orientation is the main parameter only holds at lower luminosities. At the same time, for the [...]Tunings and New Physics Searches in Neutrino Experiments
Speaker: Nina Coyle (University of Chicago)Host: Doojin Kim
Accurate neutrino-nucleus interaction modeling is an essential requirement for the success of the accelerator-based neutrino program. As no satisfactory description of cross sections exists, experiments tune neutrino-nucleus interactions to data to mitigate mis-modeling. In this talk, I will discuss how the interplay between near detector tuning and cross section mis-modeling affects [...]Boosting Light Dark Matter with Cosmic Rays and Supernovae
Speaker: Christopher Cappiello (Queen's University)Host: Doojin Kim
Direct detection experiments set strong constraints on scattering between dark matter (DM) and nuclei, but rapidly lose sensitivity when the DM mass falls below ~10 GeV. Such light DM traveling at typical halo velocities doesn't carry enough momentum to trigger traditional detectors, so new techniques or low-threshold detectors are needed [...]The Role of Ecology in Star and Planet Formation
Speaker: Megan Reiter (Rice University)Host: Grace Olivier
Most stars and planets form in clusters/associations with hundreds of low-mass stars and their associated planetary systems forming alongside each high-mass star. Radiation, energy, and momentum from the highest mass stars permeate these regions and play a central role in shaping the demographics and habitability of exoplanets. Ionizing radiation from [...]Black Holes and Long Range Forces
Speaker: Sera Cremonini (Lehigh University)Host: Christopher Pope
Recent years have seen growing efforts to understand the constraints that quantum gravity places on physics at much lower energy scales. A number of conjectures have emerged which attempt to quantify the notion that gravity is the weakest force, and identify the "swampland" of effective field theories that are inherently [...]High-precision D-meson Semileptonic Decays with Lattice QCD
Speaker: Will Jay (Massachusetts Institute of Technology)Host: Kevin Kelly
In this seminar, I will present preliminary results for D-meson semileptonic decays to pseudoscalar final states using lattice QCD. When the QCD form factors are combined with experimental measurements, these decays play a crucial role in the determination of the CKM matrix elements |Vcd | and |Vcs| and are a [...]Using Gamma Rays to Search for Low-Frequency Gravitational Waves
Speaker: Matthew Kerr (Naval Research Laboratory)Host: Justin Spilker
The hierarchical merger of galaxies and their supermassive black holes is expected to fill the universe with a low-frequency (nHz) background of gravitational waves (GWB). The amplitude and spectral shape of this GWB encodes information about black hole masses and merger dynamics. Pulsar timing arrays (PTAs) are long-term monitoring campaigns [...]New String Theories from Discrete Theta Angles
Speaker: Miguel Montero (Harvard University)Host: Katrin Becker
Topological couplings play a prominent role in our understanding of field theories, but their role in string compactifications is much less understood. I explore an example in compactifications of type IIB string theory with sixteen supercharges, showing that they lead to previously unknown components of moduli space in nine, eight, [...]Searching for New Physics in Calibration Data at Mu2e
Speaker: Ryan Plestid (Fermilab/California Institute of Technology)Host: Kevin Kelly
Mu2e is an upcoming muon conversion experiment with unprecedented sensitivity to charged lepton flavor violation. It is also an ideally suited environment in which to study two body decays (i.e. those with mono-energetic daughters) with a final state electron/positron. In their nominal run, Mu2e will use $\mu^-$ which bind to nuclei and [...]Lighting Up the Dark: Efforts to Understand the Hidden Nature of NIR-dark Galaxies
Speaker: Sinclaire Manning (University of Massachusetts Amherst)Host: Justin Spilker
Since the late 1990s, far-infrared (FIR) and (sub)millimeter extragalactic surveys have revealed a significant population of dusty star-forming galaxies (DSFGs) via thermal, dust-reprocessed ultraviolet and optical light from young, massive stars. These early works drastically altered our understanding of the prevalence of DSFGs beyond our local Universe and guided a [...]An Introduction to Flux Compactifications and Generalised Geometry
Speaker: David Tennyson (Texas A&M University)
I will review some of the key concepts in flux backgrounds of string theory/M-theory down to Minkowski space. I will focus on how one can try to understand the moduli space from the notion of G-structures, as well as how flux breaks the integrability these G-structures and hence changes the [...]Searches for New Physics with a Stopped-pion Source at the Fermilab Accelerator Complex
Speaker: Jacob Zettlemoyer (Fermilab)Host: Doojin Kim
The PIP-II complex at Fermilab is slated for operation later this decade and can support a MW-class O(1 GeV) proton fixed-target program in addition to the beam required for DUNE. Proton collisions with a fixed target could produce a bright stopped-pion neutrino source. The addition of an accumulator ring allows [...]The Weak Gravity Conjecture, BPS States, and Geometry
Speaker: Ben Heidenreich (University of Massachusetts)Host: Christopher Pope
I discuss the relationship between extremal black holes, BPS states, and the Weak Gravity Conjecture (WGC) along with their connections to Calabi-Yau geometry. In particular, the tower/sublattice WGC requires an infinite tower of BPS particles in every charge direction in which extremal BPS black holes exist. In 5d theories arising [...]Progress Towards Adaptive Optics at Visible Wavelengths with a Laser Guide Star
Speaker: Mark Ammons (Lawrence Livermore National Laboratory)Host: Justin Spilker
Adaptive Optics, a technology that compensates for the blurring caused by atmospheric turbulence, is now a common observing modality in astronomical telescopes and imaging systems. Sodium Laser Guide Stars (LGS), pointable beacons first developed by the US Air Force, have extended the sky coverage of AO systems on today’s generation [...]Searches for Long-lived Particles at the LHC
Speaker: Karri DiPetrillo (CERN)Host: Doojin Kim
Our best hope for a beyond the Standard Model discovery at the LHC requires breaking long-held assumptions about how to search for new physics. It is more important than ever before to consider complex and challenging final states that may have previously evaded standard search strategies. In this talk, I [...]The Origin of the Elements: What We Can Learn from Metal-poor Stars
Speaker: Erika Holmbeck (Carnegie Observatories)Host: Justin Spilker
The astrophysical origins of the heaviest elements found both inside and outside the Solar System are unknown, though neutron star mergers (NSMs) have been confirmed as one of their cosmic factories. Studying post-merger signals in the electromagnetic spectrum is invaluable for understanding the production of these elements at both the [...]