The Lambda-cold-dark-matter (LCDM) model has established itself as a fantastic (yet parametric) concordance model able to adjust a wide variety of cosmological observables — CMB, BBN, Large Scale Structure (LSS) & SN1a most notably. However as the precision of the data has increased over the past few years, a number of predictions of the LCDM […]
I will discuss string theory compactifications where a large number of moduli is stabilized by fluxes. I will first present a conjecture which rules out the stabilization of all complex-structure moduli in F-theory at a generic point in moduli space by fluxes that satisfy the tadpole cancellation condition. Evidence for this conjecture comes from studying K3xK3 compactifications using […]
This is a meeting on topics related to string and field theory, between members of nearby institutions: IP2I (CNRS, UCBL), Lyon LAPTh (CNRS, USMB), Annecy LPENSL (CNRS, ENSL), Lyon More information can be found on the AnLy webpage. For this second edition, the meeting will take place in IP2I, Lyon, on the 19/05/22. Talks will […]
We discuss flux compactifications of Type IIA supergravity on G2 spaces with smeared O2/O6-planes down to three dimensions. We start by presenting the setup of allowed fluxes, the internal geometry, the equations of motion and after compactification we achieve N=1 AdS3 vacua with scale that can be parametrically decoupled from the KK modes. The solutions […]
Abstract: https://arxiv.org/abs/2203.13276 https://iopscience.iop.org/article/10.3847/2041-8213/ab3e0a (1904.01765)
Modulations of X-ray spectra from extragalactic sources might provide a signature of photons converting into axion-like particles (ALPs) when traversing a region with a large-scale magnetic field. A crucial unknown in these searches is the structure of the magnetic field considered. In this talk I discuss the impact of realistic models of the magnetic field on […]
In 1976, S. Weinberg and his student, E. Gildener (GW), proposed multi-Higgs models of electroweak symmetry breaking which are clas- sically scale-invariant. If this scale invariance is spontaneously broken, the Higgs boson is the resulting massless dilaton and, of all the model’s scalars, its couplings to gauge bosons and fermions are exactly as in the […]
Cosmological first-order phase transition are said strongly supercooled when the nucleation temperature is much smaller than the critical temperature. They are typical of potentials which feature nearly scale-invariance, for which the bounce action decreases only logarithmically with time. The phase transition takes place slowly and the probability distribution of bubble nucleation time is maximally spread. […]
Abstract: The ratios $R(D^{(*)})$ are defined as the $tau/mu$ ratio of the branching fractions of exclusive semileptonic $B to D^{(*)}$ decays. They are a powerful test of Lepton Flavour Universality, one of the pillars of the SM, and are determined by the hadronic Form Factors (FFs) describing the $B to D^{(*)}$ decays. Through the novel Dispersive Matrix (DM) approach, […]
The goal of identifying the Standard Model of particle physics and its extensions within string theory has been one of the principal driving forces in string phenomenology. Recently, the incorporation of artificial intelligence in string theory and certain theoretical advancements have brought to light unexpected solutions to mathematical hurdles that have so far hindered progress […]
Abstract: For this journal club meeting I will comment on a recent paper by Albert and Rastelli (https://arxiv.org/abs/2203.11950) in which they apply modern S-matrix bootstrap techniques to the old problem of solving QCD in the large N limit. In particular, they derive universal bounds for the EFT of massless pions and find that the allowed […]