EFT, Everywhere, All at Once

Mar 16, 2026, 11:00 AM → Mar 20, 2026, 1:00 PM Europe/Zurich

4/3-006 - TH Conference Room (CERN)

Andreas Helset (CERN), Claudia Cornella, Francesco Riva, Patrick Angus Hager, Tim Cohen (CERN)

The application of effective field theory (EFT) is ubiquitous across a wide range of physical systems, from the interactions of elementary particles to the evolution of the universe. This CERN TH Institute is an interdisciplinary workshop centered on EFTs. Each day will be devoted to a different application of EFT, including the following topics:

1. EFT for colliders

2. EFT for cosmology

3. EFT for gravitational waves

4. EFT for non-relativistic systems

5. Formal developments for EFT 

 

Despite many recent advancements, most of these developments have largely occurred within separate research communities, with limited interaction between them. This workshop aims to bridge these gaps, encouraging dialogue and fostering collaboration among these diverse areas.

 

Preliminary list of speakers:

Brando Bellazzini
Martin Beneke
Kara Farnsworth
Ramona Groeber
Yiwen Huang
Denis Karateev
Dimitri Kosmopoulos
Markus Luty
Alex Pomarol
Ira Rothstein
Andrea Sanfilippo
Philipp Schicho
Dominik Schwienbacher

Mon, March 16

11:00 AM → 11:30 AM Coffee break

11:30 AM → 12:15 PM Describing New Physics by EFTs

Speaker: Ramona Grober (Università di Padova and INFN, Sezione di Padova)

EFTeverywhere_ramona.pdf

1:30 PM → 2:00 PM Coffee break

2:00 PM → 2:45 PM Factorization Beyond Coherence

I derive a novel factorization theorem for N-jettiness at hadron
colliders, which incorporates coherence-violating effects induced by
Glauber gluons and several new momentum modes. Their interplay generates
coherence-violating logarithms (CVLs) starting at four-loop (N≥1) or
five-loop order (N=0). I show the anomalous dimensions required for the
resummation of CVLs and establish a general framework for the systematic
treatment of coherence violation. The findings imply that most existing
factorization formulas for global LHC observables must be revised.

Speaker: Dominik Schwienbacher (University of Bern)

5:00 PM → 7:00 PM Unsponsored Happy Hour

Tue, March 17

10:00 AM → 10:45 AM EFT for long-wave length modes of the minimally coupled massless scalar field in De Sitter space (SdSET)

Speaker: Martin Beneke (Technische Universitaet Muenchen (DE))

11:00 AM → 11:30 AM Coffee break

11:30 AM → 12:15 PM Two-loop diffusion term in the Fokker-Planck equation from Soft de Sitter Effective Theory

Speaker: Andrea Sanfilippo (Universidad de Granada, ES)

1:30 PM → 2:00 PM Coffee break

2:00 PM → 2:45 PM Anomalous dimension for principal series fields in de Sitter space

Speaker: Yiwen Huang (Kavli IPMU (JP))

Wed, March 18

10:00 AM → 10:45 AM Kara Farnsworth - Hamiltonian Truncation and Effective Field Theory

Hamiltonian truncation is a nonperturbative numerical method for calculating observables of a quantum field theory by truncating the Hilbert space to states with energy below a maximum energy cutoff. In this talk I will provide an overview of effective field theory techniques applied to Hamiltonian truncation calculations, focusing on improving convergence and handling marginal interactions in a 2d example system.

11:00 AM → 11:30 AM Coffee break

11:30 AM → 12:15 PM 2D U(1) Chiral Gauge Theory on a Computer

Speaker: Markus Luty

1:30 PM → 2:00 PM Coffee break

2:00 PM → 3:00 PM TH colloquia - A Unified Approach to the Self-Force Problem

Speaker: Ira Rothstein (CMU)

5:00 PM → 7:00 PM Unsponsored Happy Hour

Thu, March 19

10:00 AM → 10:45 AM Killing EFTs with positivity

Speaker: Alex Pomarol Clotet (Universitat Autònoma de Barcelona (ES))

11:00 AM → 11:30 AM Coffee break

11:30 AM → 12:15 PM Trace anomalies and the dilation-graviton amplitude

We consider 3+1 dimensional Quantum Field Theories (QFTs) coupled to the dilaton and the graviton. We show that the graviton-dilaton scattering amplitude receives a universal contribution which is helicity flipping and is proportional to (∆c − ∆a) along any RG flow, where ∆c and ∆a are the differences of the UV and IR c- and a-trace anomalies respectively. This allows us to relate (∆c − ∆a) to spinning massive states in the spectrum of the QFT. We test our predictions on a simple example of a massive free scalar. We discuss possible applications

Speaker: Denis Karateev (Universite de Geneve (CH))

1:30 PM → 2:00 PM Coffee break

2:00 PM → 2:45 PM Detector Amplitudes

Speaker: Brando Bellazzini

Fri, March 20

8:55 AM → 9:40 AM Construction and limitations of EFTs for hot QFT

Finite-temperature effective field theories (EFTs) were originally developed to study thermodynamics and phase transitions in non-Abelian gauge theories. More recently, they have experienced renewed interest as a tool for determining soft contributions to real-time lightcone observables.

In the context of cosmological phase transitions, the construction of such EFTs has reached new levels of automation. In particular, full dimension-six thermal hot EFTs have recently been constructed, including hot SMEFT. In this talk, I will discuss recent progress in building these EFTs, as well as their limitations. I will also briefly highlight alternative techniques, including the heat-kernel and Hilbert-series approaches at finite temperature.

Finally, I will discuss applications of these EFTs to cosmological phase transitions and outline both old and new strategies to systematically extend perturbative control beyond the high-temperature regime, enabling reliable descriptions across a wider range of temperatures.

Speaker: Philipp Schicho (University of Geneva)

10:00 AM → 10:30 AM Coffee break

10:30 AM → 11:15 AM Shell EFT, Everywhere, All Orders at Once

A key property that shapes the gravitational waveform of binary systems is the tidal deformability of their constituents, quantified by the Love numbers. In modern treatments of the gravitational two-body problem, the binary dynamics are described within an effective field theory (EFT), where Love numbers enter as Wilson coefficients encoding the finite-size response of each object. In this talk, I will introduce Shell Effective Field Theory, a new framework for computing the classical gravitational dynamics of compact objects, with particular emphasis on extracting Love numbers. By combining techniques from quantum field theory with solutions to black-hole perturbation theory, Shell EFT circumvents the loop integrations that constitute the main bottleneck in conventional approaches. I will present new results for dynamical Love numbers of generic compact objects through order G^9, corresponding to an eight-loop calculation, and conjecture their all-orders structure in the case of a Schwarzschild black hole.

Speaker: Dimitri Kosmopoulos