College of Arts and Sciences

A New Leading Mechanism for Neutrinoless Double-Beta Decay

… or how to attract the ire of the community. The neutrinoless double-beta decay of nuclei is essentially the only way to test lepton-number violation coming from the possible Majorana character of neutrinos. Tremendous effort is dedicated to its measurement and to reducing the theoretical uncertainty in the calculation of the nuclear matrix elements needed for its interpretation. Well, we increase the uncertainty.

Continue reading… Bira van Kolck (Institut de Physique Nucleaire d’Orsay and University of Arizona)

Bispectrum Bias Loops and Power Spectrum Covariance

I will discuss recent progress in two topics in large-scale structure: 1) understanding galaxy bias beyond leading order in perturbation theory and its application to the bispectrum, and 2) how to model the covariance of the galaxy power spectrum multipoles analytically instead of using numerical simulations.

Continue reading… Roman Scoccimarro (NYU)

Linking Corrections to Entropy and Extremality

I will prove that the leading perturbative corrections to the entropy and extremality bounds of black holes are directly proportional to each other, generically.  This fact is intimately related to the Weak Gravity Conjecture, as I will discuss. The proof is purely thermodynamic and applies to systems beyond the gravitational realm.

Continue reading… Garrett Goon (CMU)

Quantum Algorithms for Collider Physics

As particle physics experiments continue to stretch the limits of classical computation, it is natural to ask about the potential future role of quantum computers.  In this talk, I discuss the potential relevance of quantum algorithms for collider physics.  I present a proof-of-concept study for “thrust”, a well-known collider observable that has O(N^3) runtime for a collision involving N final-state particles.  Thrust is a particularly interesting observable in this context, since it has two dual formulations, one which naturally maps to quantum annealing and one which naturally maps to Grover search. 

Continue reading… Jesse Thaler (MIT)

The QCD Axion and Unification

The QCD axion is one of the most appealing candidates for the dark matter in the Universe. In this article, we discuss the possibility to predict the axion mass in the context of a simple renormalizable grand unified theory where the Peccei-Quinn scale is determined by the unification scale. In this framework, the axion mass is predicted to be in the range ma ≃ (3 − 13) × 10−9 eV. We study the axion phenomenology and find that the ABRACADABRA and CASPEr-Electric experiments will be able to fully probe this mass window.

Continue reading… Clara Murgui (IFIC, Valencia)

Dark Matter Research with Bound Systems
 
My discussion will rest on three pillars. The first is an overview of bound states in dark sectors, and their implications for dark matter phenomenology, mass predictions and dark matter model building. The second is an exploration of new experimental techniques, which are needed to search for dark matter, which resides in a sector containing bound states. Finally, I will discuss some experimental observations based on bound states of ordinary matter, which can be used to constrain some of the introduced dark matter scenarios.

Continue reading… Juri Smirnov (Ohio State University)

Black-Hole Lattices as Cosmological Models

Challenges for modern cosmology include determining the influence the small-scale structure has in the universe on its large-scale dynamics and observations. With numerical relativity tools, finding and exploring cosmological models which are exact solutions to the Einstein equations will resolve all the non-linearities so that give us hints on quantifying the influence. In this talk, I will introduce Black-Hole Lattice models, which are subsets of relativistic discrete cosmological models. In particular, I will start from constructing those spacetimes and show what we can learn from exploring their properties.

Continue reading… Chi Tian (CWRU)

Electroweak measurements at electron-positron colliders as indirect searches for heavy neutrinos

Heavy neutrinos are part of many extensions of the Standard Model, in particular seesaw models that can explain the light neutrino masses and mixing. Future electron-positron colliders would greatly increase the precision of the measurements of electroweak processes. I will discuss how this improved precision offers new opportunities to search for the effects of heavy neutrinos. In particular, I will focus on indirect search strategies based on the modifications of the production cross-sections of W or Higgs bosons at linear collider. These searches are complementary to other observables and would allow to probe the multi-TeV mass regime at future colliders.

Continue reading… Cedric Weiland (University of Pittsburgh)

Searching for low mass dark matter particles at SNOLAB

90 years after its first evidence by F Zwicky, the nature of the dark matter of the Universe  is still unknown. There is a consensus it should be made of elementary particles but their search has been going on for several decades without success. Huge progress in sensitivity has been done, though,  thanks to new innovative detection techniques. Indeed some new techniques allow to enlarge the exploration of parameter space.  I will describe status of two projects I have developed, within international collaborations, thanks to a CERC grant in Canada,

Continue reading… Gilles Gerbier (Queen’s U)

Massive Gravitons in Curved Spacetimes

This talk will cover various interesting topics that occur in massive spin-2 on various spacetimes
including de Sitter, anti-de Sitter, and flat space. In de Sitter, we examine what happens to massive
gravity as its mass approaches the partially massless value. In this limit, if the interactions are
chosen to be precisely those of the ’candidate’ non-linear partially massless theory, the strong
coupling scale is raised, giving the theory a wider range of applicability. In anti-de Sitter and flat
spacetime, we show how shift symmetries acting on the vector modes emerge from massive spin-2
theories fixing the non-linear structure and discuss whether these theories have amplitudes that
can be constructed via soft substracted recursion.

Continue reading… Laura Johnson (CWRU)

The fall and rise of parity and the origin of (neutrino) mass

Continue reading… Goran Senjanovic (ICTP, Trieste)

Strong CP violation: fancy and fact

Continue reading… Goran Senjanovic (ICTP, Trieste)

Born-Infeld Electrodynamics at One-Loop

The Born-Infeld model is an effective field theory of central importance describing the low-energy dynamics of massless gauge bosons on the world-volume of D-branes. Though it is in many ways exceptional in the universality class of models of nonlinear electrodynamics, several aspects of the physics of the Born-Infeld model remain mysterious. In this talk I will explain how aspects of the model, obscured in the traditional formulation of Lagrangian field theory, are clarified by directly studying the on-shell S-matrix. In particular in 3+1-dimensions, classical Born-Infeld has an electromagnetic duality symmetry which manifests in tree-level scattering amplitudes as the conservation of a chiral charge.

Continue reading… Callum Jones (University of Michigan)

Striped and Superconducting Phases in Holography

There is a duality out of the framework of string theory that tells us, in certain cases, gravity can be thought of as emerging from the quantum mechanical degrees of freedom of a system. Remarkably, this relationship has not only given us a long sought after microscopic description of black holes and insights into the fabric of spacetime, but has also proven itself useful as a novel analytic toolset to investigate non-perturbative systems. Known as holography, this weak/strong coupling duality allows us to examine strongly coupled quantum systems by mapping them to perturbative, 

Continue reading… Erin Blauvelt (Lehigh University)

Cosmological Seed Magnetic Field from Inflation

A cosmological magnetic field of nG strength on Mpc length scales could be the seed magnetic field needed to explain observed few microG large-scale galactic magnetic fields. I first briefly review the observational and theoretical motivations for such a seed field, two galactic magnetic field amplification models, and some non-inflationary seed field generation scenarios. I then discuss an inflation magnetic field generation model. I conclude by mentioning possible extensions of this model as well as potentially observable consequences.

Continue reading… Bharat Ratra (Kansas State University)