TPPC weekly seminar (in-person): Jordan Koechler - Consistency of the Galactic Center Excess with cosmological and laboratory observations via leptophilic dark matter in U(1)Li−Lj models

Wednesday 22 Oct 2025, 12:30 → 13:45 Europe/London

The particle nature of dark matter remains one of the most important open questions in physics. An intriguing clue is the γ-ray excess observed by Fermi-LAT toward the Galactic Center, whose spectrum resembles the expected signal from annihilating weakly interacting massive particles. However, many conventional dark matter models are now strongly constrained by direct detection and collider experiments. In this talk, I will explore a class of anomaly-free extensions of the Standard Model based on gauged lepton-number differences, U(1)Li​−Lj​​, as well as U(1)B−L​. I will show how these models can simultaneously account for the Galactic Center excess, satisfy the relic abundance requirement, and remain consistent with laboratory and cosmological constraints. Particular attention will be given to the Lμ​−Le​ model, which not only provides a good fit to the data but also connects naturally with the long-standing (g−2)μ,e​ anomalies.