Baryon Acoustic Oscillations (BAO) are a powerful cosmological probe that provide a standard ruler to map the expansion history of the Universe. By measuring BAO at different redshifts, we can trace how the Universe has expanded over time and place constraints on dark energy and other cosmological parameters. The Dark Energy Spectroscopic Instrument (DESI) has now released its Year 3 results (Data Release 2), comprising BAO measurements from over 14 million galaxies and quasars. These results, when combined with complementary measurements such as the cosmic microwave background (CMB) and supernovae, show intriguing tensions with the standard ΛCDM model. In this seminar, we will give an overview of the DESI DR2 results, highlighting the evidence for deviations from ΛCDM. Finally, we will discuss some interesting particle physics possibilities and their status after the latest data releases by ACT-DR6 and DESI DR2.
Giada Caneva, Elia Bertoldo, Francesco Sciotti