Journeys in Effective Field Theories

24 Sept 2025, 09:00 → 26 Sept 2025, 16:00 Europe/Berlin

28B 110 (RWTH)

Effective Field Theories (EFTs) are an essential tool for the modern-day particle physicists. EFTs are used to organise our knowlegde and to parametrise our ignorance. Indeed, not only they allow to describe physical regimes retaining only the relevant information, but they are also necessary in the context of perturbation theory when several energy scales (know or unknown) are involved.

These (mostly blackboard) lectures will provide an introduction and overview of the most common and relevant EFTs, from the Fermi theory to the Standard Model Effective Field Theory, and cover important aspects such as matching and renormalisation group effects.

The exercise sessions are meant to provide examples of how EFTs and related techniques are used everyday in the exploration of physics beyond the Standard Model.

Wednesday 24 September

1 EFT intro: theory with separation of scales

Speaker: Christophe Grojean (DESY & Humboldt U.)

2 Various examples of EFTs that you know of

Speaker: Christophe Grojean (DESY and Humboldt U.)

3 Exercices: electroweak precision data and oblique corrections

Speaker: Christophe Grojean (DESY and Humboldt U.)

Aachen_2025_ex.pdf

Thursday 25 September

4 Standard Model Effective Field Theory (aka SMEFT), UV assumptions and power counting

Speaker: Christophe Grojean (DESY and Humboldt U.)

5 EFT at one-loop: renormalisation group mixing. EFTs at Future Colliders

Speaker: Christophe Grojean (DESY and Humboldt U.)

6 Renormalisation Group in SMEFT. BSM one-loop sensitivity from EW measurements at FCC-ee

Speaker: Lukas Allwicher (T (Phenomenology))

Friday 26 September

7 Flavour assumptions and symmetries in SMEFT

Speaker: Lukas Allwicher (DESY)

8 Exercices: Matching (pen & paper and tools)

Speaker: Lukas Allwicher (DESY)

EFT_exercise_session.pdf

9 Exercices: Bounding new particle masses

Speaker: Lukas Allwicher (DESY)