College of Arts and Sciences

Coupling Galaxy Evolution and the Epoch of Reionization

The Epoch of Reionization is a pivotal period in our cosmic history, representing the transition from a neutral post-recombination Universe into the fully ionized one we observe today. The procession of reionization is dictated by the fraction of ionizing photons, fesc, that escapes from galaxies to ionize the inter-galactic medium, with the exact value and functional form still an open question. I explore this question using the Semi-Analytic Galaxy Evolution (SAGE) model to generate galaxy properties, such as the number of ionizing photons emitted, and follow different possible Epoch of Reionization scenarios with a semi-numerical scheme.

Continue reading… Jacob Seiler (Swinburne University of Technology, Melbourne)

Electroweak Baryogenesis, ACME II, and Dark Sector CP Violation
 
The origin of the matter-anti-matter asymmetry in the universe is a big puzzle for particle physics and cosmology. Baryogenesis mechanisms at the electroweak
scale are attractive for their testability at high-energy colliders and low-energy experiments. The recent measurement of electron electric dipole moment by ACME II sets stringent limit on weak scale CP violations and challenges the viable parameter space for successful electroweak baryogenesis in traditional models, such as two-Higgs doublet models and supersymmetry. In this talk, I will present our recent proposal of triggering electroweak baryogenesis with dark sector CP violation,

Continue reading… Yue Zhang (Fermilab)

Unification and Precision Measurements
 
Abstract: The Standard Model of particle physics may yet be unified into a deeper organizing principle. The gauge groups may unify into higher rank gauge group, and the Yukawa couplings might unify into a simplifying symmetry group. The key to assessing these unification prospects is precision measurements and related precision theory. The current status of unification, in its various guises, is discussed from the perspective of precision analysis. In addition, the prospects for further stress-testing the ideas at future experiment and through future theory work are also presented.

Continue reading… James Wells (University of Michigan-Ann Arbor)

The NANOGrav 11-year Data Set: New Insights into Galaxy Growth and Evolution

Giant telescopes, exoplanets, and astronomy in the 2020s

New Physics at Neutrino Telescopes

Abstract: The recent observation of high-energy neutrinos at the IceCube neutrino telescope has opened a new era in neutrino astrophysics.  Understanding all aspects of these events is very important for both Astrophysics and Particle Physics ramifications.  In this talk, I will discuss a few possible new physics scenarios, such as dark matter, leptoquarks and supersymmetry, that could be probed using the IceCube data.  I will also relate this to the puzzling observation of two upgoing EeV events recently made by the ANITA experiment, which were not seen by IceCube.

Continue reading… Bhupal Dev (Washington University)

Breaking Mirror Hypercharge in Twin Higgs Models
 
The Twin Higgs is a novel framework to understand the stability of the Higgs mass in the face of increasingly stringent LHC bounds on colored top partners. Two principal structural questions in this framework concern the nature of the twin hypercharge gauge symmetry and the origin of the Z2 symmetry breaking needed to achieve the correct vacuum alignment. After an introduction to this framework, a simple extension of the Mirror Twin Higgs model with an exact Z2 symmetry is presented in which a new scalar field in the twin sector spontaneously breaks both twin hypercharge and Z2.  

Continue reading… Brian Batell (University of Pittsburgh )

Supersymmetry, Hidden Sectors, and Baryogenesis
 
Abstract:  Supersymmetry has been a primary target for the experiments at the Large Hadron Collider.  We review what the absence of supersymmetric signals thus far implies for supersymmetric extensions to the Standard Model.  We discuss ways in which supersymmetry might still have important consequences for our Universe — even if it does not completely explain the hierarchy between strength of gravity and the other forces.  As an example, we discuss how a supersymmetric extension might be responsible for generating the observed symmetry between matter and anti-mattter.

Continue reading… Aaron Pierce (University of Michigan-Ann Arbor)

Constraining the gravitational sector with black hole perturbations

Searching for the dark sector in neutrino detectors
 
Abstract: Dark matter has thus far eluded attempts to determine its non-gravitational interactions, putting strong constraints on a minimal dark sector. I present models of non-minimal dark sectors that could elude current searches, but be seen in current or near future neutrino experiments. I begin by presenting a comprehensive, ongoing phenomenological study of models in which dark matter can annihilate into other forms of dark matter, leading to a flux of energetic (boosted) dark matter (BDM). Such dark matter could deposit enough energy to be detected in large neutrino detectors such as Super-Kamiokande and DUNE.

Continue reading… Joshua Berger (University of Pittsburgh)

Shift Symmetries in (Anti) de Sitter Space

Tau-philic dark matter coannihilation at the LHC and CLIC 

Abstract: We will discuss a set of simplified models of dark matter with three-point interactions between dark matter, its coannihilation partner and the Standard Model particle, which we take to be the tau lepton. The contribution from dark matter coannihilation is highly relevant for a determination of the correct relic abundance. Although these models are hard to detect using direct and indirect detection, we will show that particle colliders can probe large regions in the parameter space. Some of the models discussed are manifestly gauge invariant and renormalizable,

Continue reading… Alexis D. Plascencia (CWRU)