Person

Timothy Cohen

Superadditivity at large charge

The weak gravity conjecture has been invoked to conjecture that the dimensions of charged operators in a CFT should obey a superadditivity relation (sometimes referred to as convexity). In this paper, we study superadditivity of the operator spectrum in th ...

Springer Science and Business Media LLC2025

Geometry of soft scalars at one loop

Filippo Nardi, Timothy Cohen

We extend the soft theorems for scattering amplitudes of scalar effective field theories to one-loop order. Our analysis requires carefully accounting for the fact that the soft limit is not guaranteed to commute with evaluating IR-divergent loop integrals ...

Springer Science and Business Media LLC2025

What is the geometry of effective field theories?

Timothy Cohen

We elaborate on a recently proposed geometric framework for scalar effective field theories. Starting from the action, a metric can be identified that enables the construction of geometric quantities on the associated functional manifold. These objects tra ...

American Physical Society (APS)2025

Operator origin of anomalous dimensions in de Sitter space

Timothy Cohen

The late-time limit of the power spectrum for heavy (principal series) fields in de Sitter (dS) space yields a series of polynomial terms with complex scaling dimensions. Such scaling behavior is expected to result from an associated operator with a comple ...

American Physical Society (APS)2025

Recursion for Wilson-line form factors

Timothy Cohen

Matrix elements of Wilson-line dressed operators play a central role in the factorization of soft and collinear modes in gauge theories. When expressed using spinor helicity variables, these so-called form factors admit a classification starting from a Max ...

SPRINGER2024

On amplitudes and field redefinitions

Timothy Cohen

We derive an off-shell recursion relation for correlators that holds at all loop orders. This allows us to prove how generalized amplitudes transform under generic field redefinitions, starting from an assumed behavior of the one-particle-irreducible effec ...

SPRINGER2024

Dark sector glueballs at the LHC

Timothy Cohen

We study confining dark sectors where the lightest hadrons are glueballs. Such models can provide viable dark matter candidates and appear in some neutral naturalness scenarios. In this work, we introduce a new phenomenological model of dark glueball hadro ...

Springer Nature2024

Effective field theory of the two Higgs doublet model

Timothy Cohen

We revisit the effective field theory of the two Higgs doublet model at tree level. The introduction of a novel basis in the UV theory allows us to derive matching coefficients in the effective description that resum important contributions from the Higgs ...

Springer Nature2023

Dynamics of stellar disc tilting from satellite mergers

Timothy Cohen

The Milky Way's stellar disc can tilt in response to torques that result from infalling satellite galaxies and their associated tidal debris. In this work, we explore the dynamics of disc tilting by running N-body simulations of mergers in an isolated, iso ...

2023

Anomalies from the covariant derivative expansion

Timothy Cohen

We revisit the calculation of chiral anomalies for global and gauge symmetries in the framework of the covariant derivative expansion (CDE). Due to the presence of UV divergences, the result is an ambiguous quantity that depends on the regularization proce ...

American Physical Society2023