The international CUPID-Mo experiment conducted by French laboratories of IN2P3, CEA/IRFU and CEA/IRAMIS has been testing the use of Molybdenum-based crystals since last April to detect double beta decay without neutrino emission. The experiment is gradually gaining strength and already shows a near-zero background in the region of interest, which is very promising. The scientists of the collaboration made an update in the occasion of the official inauguration on 11 and 12 December 2019.


A few microseconds after the Big Bang the Univers may have gone through a deconfined state of quarks and gluons, the Quark–Gluon Plasma (QGP). The QGP can be recreated in high-energy heavy-ion collisions. In particular at the LHC at CERN, the QGP behaves like a fluid. All particles, light, strange, or charmed flow collectively as if being carried by the same fluid, proving the strength of the interactions between QGP constituents. The ALICE Collaboration at the LHC, with decisive contributions from the Irfu teams, has just published, in the prestigious Physical Review Letters journal, the first measurement of the elliptic flow of Υ(1S) (a particle composed of a beauty quark and its antiquark). This resonance appears as the first particle at the LHC not flowing with the fluid. This pioneering result opens up the path for deeper studies of the QGP.


To measure cosmological parameters, the Euclid space telescope will use two main probes: gravitational lensing (Weak Gravitational Lensing) and galaxy distribution (Galaxy Clustering). These measurements will allow us to study dark energy and dark matter, which affect the growth of cosmic structures and the accelerated expansion of the Universe.

In addition to its implications on instrumental developments and data processing, Irfu is actively involved in the development of algorithms needed to prepare the extraction of cosmological parameters that will be derived from Euclid measurements.

Coordinated by Valeria Pettorino, physicist at Irfu's CosmoStat laboratory, in collaboration with Tom Kitching (UCL[1]) and Ariel Sanchez (MPE[2]), an international team from the Euclid collaboration with complementary expertise in theory and observation has just completed a 3-year study characterizing the performances expected from Euclid for these observational probes.

Publication an Arxiv: https://arxiv.org/pdf/1910.09273.pdf

[1] University College London ; [2] Max Planck Institute for extraterrestrial physics
A collision of the Milky Way with a small galaxy accurately dated by the study of the star ν Indi

ν Indi is a bright star (visual magnitude mv = 5.3) visible with the naked-eye from the southern hemisphere. By using ground data (ESO telescopes), space data (Gaia and Tess missions) and by combining very diverse spectroscopic, astrometric, kinematic or asteroseismological information, an international team including two researchers from the Department of Astrophysics / AIM Laboratory of CEA-Saclay was able to determine the epoch, between 11.6 and 13.2 billion years ago, of a collision between our galaxy and a small dwarf galaxy, Gaia-Enceladus. This work is published in the journal Nature Astronomy, January 2020.


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