Journées de Rencontre Jeunes Chercheur·se·s 2025

Session

Theory

3 déc. 2025, 11:35

Présidents de session

Theory

• Jonathan Kriewald (Jožef Stefan Institute)

Theory

• Jonathan Kriewald (Jožef Stefan Institute)

46. Session overview

Jonathan Kriewald (Jožef Stefan Institute)

03/12/2025 11:35

10. Freeze-in with low reheating temperature

Thomas REGGIO (LPCA)

03/12/2025 12:05

Theory

The freeze-in mechanism is an alternative mechanism for dark matter production to standard thermal freeze-out. Freeze-in computations are typically performed assuming a very high initial ("reheating") temperature. However, this temperature is poorly constrained and can take relatively small values. I will discuss dark matter freeze-in in such a scenario and highlight how dark matter production...

55. Scalar waves beyond eikonal approximation

Emma Bruyere (IAP)

04/12/2025 08:55

Theory

The propagation of gravitational waves shares formal similarities with that of light. However, their typically much larger wavelengths render the geometric optics — or eikonal — approximation insufficient when considering propagation in curved spacetime. The purpose of this thesis is to establish a systematic framework that goes beyond this approximation, and to assess its implications for the...

11. Self-interacting neutrinos in light of recent CMB and LSS data

Adèle Poudou (LUPM)

04/12/2025 09:20

Cosmology

We update constraints on a simple model of self-interacting neutrinos involving a heavy scalar mediator with universal flavor coupling. According to past literature, such a model is allowed by Cosmic Microwave Background (CMB) data, with some CMB and large-scale structure data even favoring a strongly-interacting neutrino (SI$\nu$) scenario over $\Lambda$CDM. In this work, we re-evaluate the...