Microlensing signatures of extended dark objects using machine learning

This paper presents a machine learning-based method for the detection of the unique gravitational microlensing signatures of extended dark objects, such as boson stars, axion miniclusters and subhalos. We adapt MicroLIA, a machine learning-based package tailored to handle the challenges posed by low-cadence data in microlensing surveys. Using realistic observational time stamps, our models are trained on simulated light curves to distinguish between microlensing by pointlike and extended lenses, as well as from other object classes which give a variable magnitude. We focus on boson stars and Navarro-Frenk-White (NFW) subhalos and show that the former, which are examples of objects with a relatively flat mass distribution, can be confidently identified for 0.8 ≲ r=rE ≲ 3. Intriguingly, we also find that more sharply peaked structures, such as NFW subhalos, can be distinctly recognized from point lenses under regular observation cadence. Our findings significantly advance the potential of microlensing data in uncovering the elusive nature of extended dark objects. The code and dataset used are also provided

Non-universal Z′Z' from Fluxed GUTs

We make a first systematic study of non-universal TeV scale neutral gauge bosons $Z'$ arising naturally from a class of F-theory inspired models broken via $SU(5)$ by flux. The phenomenological models we consider may originate from semi-local F-theory GUTs arising from a single $E_8$ point of local enhancement, assuming the minimal ${\cal Z}_2$ monodromy in order to allow for a renormalisable top quark Yukawa coupling. We classify such non-universal anomaly-free $U(1)'$ models requiring a minimal low energy spectrum and also allowing for a vector-like family. We discuss to what extent such models can account for the anomalous $B$-decay ratios $R_{K}$ and $R_{K^*}$.Comment: 14 page

Topics on modern String phenomenology

In this thesis we present phenomenological consequences of the modern nonperturbative regimes of String Theory, M- and F-Theory. The origins of SO(10) from M-Theory on G2 manifolds are discussed, accompanied by a detailed discussion on a rank-breaking mechanism and consequences for neutrino masses. The Minimal Supersymmetric Standard Model is derived from F-Theory compactifications exhibiting a spectral cover equation with Klein monodromy and a geometric parity that endows the spectrum with an effective matter parity. A dedicated and systematic study on R-Parity violating couplings in F-Theory is also presented, where we find these couplings to be generic, and we compute their magnitudes