Theory Division

We study the propagators of a scalar field coupled to a lattice regularization of gravity in the limit there is no back-reaction from the matter.  We extract the renormalized mass, and binding energy between scalar particles and attempt to recover the known, non-relativistic, tree-level calculation in the infinite-volume, continuum limit  for the scaling of the... More »

Over the past five decades, Euclidean lattice field theory has matured into a broad program capable of making precise QCD predictions. While its success is undeniable, certain problems in real time and at finite density elude it due to sign problems. Early on, Feynman pointed out that many of these problems are naturally solvable on... More »

We propose extending the search for dark matter (DM) by considering muon spin targets.  An ultralight DM background may apply an oscillating torque to muon spins, resulting in novel precession trajectories.  A time-resolved analysis of muon precession data from the upcoming Fermilab and J-PARC g-2 experiments and future frozen spin EDM measurements are sensitive to... More »

Although it is known to provide the gravitational scaffolding of our universe, the existence of dark matter is a mystery that cannot be explained by our current understanding of fundamental particle physics. Recent years have seen a growing interest in applying developing technologies to enable qualitatively new ways to look for types of dark matter... More »

In the first part of the talk I will discuss gravitational wave signature arising from first order phase transition in two different models featuring neutrino mass generation through type-I seesaw mechanism. The expected gravitational wave spectra from these models will be confronted with sensitivities of ground-based detectors such as LIGO as well as several future... More »

The diphoton channel at lepton colliders, e+e-  (mu+mu-) ->  gamma gamma, has a remarkable feature that the leading new physics contribution comes only from dimension-eight operators.  This contribution is subject to a set of positivity bounds,  derived from fundamental principles of Quantum Field Theory, such as unitarity, locality, analyticity and Lorentz invariance.  These positivity bounds are thus... More »

The problems of dark matter, quantum gravity and the early universe show that physics beyond the Standard Model must be out there, but its nature remains a mystery. In this seminar, I will describe new experimental and theoretical ideas to expand our search for new physics. I’ll talk about how searches for dark matter candidates,... More »

Direct detection is notoriously hard for a plethora of dark matter models and models of dark relics due to their inability to impart enough energy to the direct detection target. Detecting these dark relics with energy deficit involves tackling the twin challenges of a target that can convert small amounts of dark matter kinetic energy... More »

Higgs boson pair production is the most promising process for testing the scalar potential of the SM beyond the quadratic term. The next-to-leading order QCD corrections for this gluon-fusion process are large and the dependence on the renormalization scheme of the top quark mass are sizeable.   In this seminar I will discuss the current... More »

The importance of detecting neutrinos from a Milky Way core-collapse supernova is well known.  An under-studied phase is proto-neutron star cooling.  With the high statistics expected for present and near-future detectors, it should be possible to obtain detailed neutrino signals from before the start of the cooling phase to very late times.  We present the... More »