The observation of the neutrino burst coming from the next Galactic Core-Collapse SuperNova (CCSN) and its gravitational wave and electromagnetic counterparts will provide us invaluable information on this extreme phenomenon. KM3NeT is a neutrino telescope consisting of two detectors, ORCA and ARCA, currently under deployment in the Mediterranean Sea. By searching for an excess of coincidences above the optical background, KM3NeT is able to detect low energy neutrinos coming from CCSN. The sensitivity to Galactic and near-Galactic events is expected when data from the two infrastructures is combined. With its integration in the SNEWS global alert network and the ongoing work to compute, transmit and combine the neutrino light-curves of different detectors, KM3NeT will play a key part in notifying other telescopes before the arrival of the other messengers. In this contribution, we present the real-time detection capabilities of KM3NeT, the additional information that can be brought by light-curve computations and the follow-up of external alerts.
With its ability to observe the Universe with NISP, a near infrared spectrophotometer and VIS in visible light, Euclid will probe redshifts up to z = 2, with an expected spectroscopic sample of 35 million galaxies and a photometric sample of 1.5 billion galaxies. Providing good photometric redshifts for the photometric sample is crucial in weak lensing analyses but also for galaxy clustering. In this context, we study how accurate a deep learning approach can be using Euclid data. We then make use of this very large number of galaxies to perform a photometric galaxy clustering analysis and provide constraints on cosmological parameters. A tomographic approach allows us to get constraints on H0 with a BAO analysis as well as constraints on the evolution of the expansion of the Universe, characterized by the dark energy equation of state parameters w0 and wa with a full-shape analysis. Moreover, controlling systematics is especially important, which is why the influence of redshift distribution misspecifications over cosmological constraints is studied in the context of the full-shape analysis.
The standard model assumes that the three charged leptons, electrons $e$, muons $\mu$, and taus$\tau$, have an identical electroweak coupling,
and the distinction arises from their different masses. Several independent experiments, including BaBar, Belle, and LHCb, have found deviations from SM predictions. Some of these anomalies arises in the $b\to c \ell \nu$ transition, referred to as \textit{charged anomalies}.
The overall tension between theoretical predictions based on the Standard Model and the world-average including recent measurements remains at the 3$\sigma$ level.
The goal of my thesis is to test the lepton flavor universality by comparing the decays $B^0 \to D^{*} \tau \nu_\tau $ to $B^0 \to D^{*} \mu \nu_\mu $ where $\tau$ is reconstructed from its decay products $\pi^+\pi^-\pi^+(\pi^0)$,
using data collected by the LHCb detector between 2011 and 2018. With larger statistical sample, we will be able to significantly reduce the uncertainty of the measurement.