# Théorie

# TBA

# Behavior of three-point functions in inflationary and bouncing scenarios

Inflation has been widely regarded as the most promising scenario to explain our observations of the early universe. However, in view of the difficulties associated with arriving at a unique model of inflation, it seems worthwhile to investigate alternative scenarios of the early universe, specifically the so-called bouncing models.

# TBA

# Long lived light scalar in the minimal left-right symmetric model

In the minimal left-right symmetric model which could accommodate the tiny neutrino masses via TeV seesaw mechanism, the neutral scalar from the right-handed symmetry breaking sector could be much lighter than the electroweak scale. We discuss the constraints on this particle from low-energy flavor observables, e.g. meson oscillations and rare decays, and find that such a light particle is necessarily long-lived, and can be searched for at the LHC via displaced signals of a collimated photon jet, if its mass is of order GeV scale.

# Stueckelberg massive electromagnetism in de Sitter and anti-de Sitter spacetimes: Two-point functions and renormalized stress-energy tensors

We discuss Stueckelberg massive electromagnetism on an arbitrary four-dimensional curved spacetime. By considering Hadamard vacuum states, we construct the two-point functions associated with Stueckelberg massive electromagnetism in de Sitter and anti-de Sitter spacetimes. We present the Hadamard renormalization of the expectation value of the stress-energy-tensor operator, and we provide its explicit expression for the Stueckelberg theory.

# Chiral electrodynamics in astrophysics and cosmology

# New Directions in Dark Matter Direct Detection

Sub-GeV dark matter is a theoretically motivated but largely unexplored paradigm of dark matter. In this talk, I will discuss recent work on the direct detection of sub-GeV dark matter through dark matter-electron scattering. I will present some motivated models that can be probed with these techniques as well as projections for current and near-term noble liquid, semiconductor, and scintillator experiments. Finally, I will discuss some new techniques that may allow us to more robustly discriminate between dark matter signatures and background.

# Late time cosmology with LISA: probing the cosmic expansion with massive black hole binary mergers as standard sirens

I will summarize the potential of the LISA mission to constrain the expansion history of the universe using massive black hole binary mergers as gravitational wave standard sirens. After briefly reviewing the concept of standard siren, I will outline the analysis and methodologies to use LISA as a cosmological probe, and present estimates for the power of LISA in constraining cosmological parameters for both standard and alternative cosmological models.

# Galactic sources: update information from gamma-rays experiments and implications for IceCube

Air-Cherenkov telescopes have mapped the Galactic plane at TeV

energies. Here we evaluate the prospects for detecting the neutrino

emission from sources in the Galactic plane assuming that the highest

energy photons originate from the decay of pions. Four promising

sources are identified based on having a large flux and a flat

spectrum. We subsequently evaluate the probability of their

identification above the atmospheric neutrino background in IceCube

data as a function of time. We show that observing them over the