Ricerc@Sapienza

The goal of this research project is to contribute to the search for low mass Dark Matter (DM) candidates. In particular I'm interested in the direct detection experimental effort, that is the direct observation of nuclear recoils in underground detectors induced by the DM.

The search for Dark Matter weakly interacting massive particles with noble liquids has probed masses down and below a GeV/c^2, corresponding to an experimental threshold equivalent to a few ionization electrons. In these conditions, the energy taken by the so-called Migdal electron could be sizable compared to the energy of the induced nuclear recoil. In a recent publication [1], we showed how such an effect allows us to push the experimental sensitivity of liquid argon experiments down to masses of 0.1 GeV/c^2, extending the search region for dark matter particles of previous results. The Migdal effect [2] is then a promising handle to improve the sensitivity of the DM direct detection experiments to light DM candidates, but it has not been measured yet. This has been the subject of my PhD studies [1], which, in the context of the two international collaborations DarkSide-20k and CYGNO, were focused both on phenomenological and experimental aspects of the search for low mass DM. I will therefore further extend my work, and in particular in the context of the CYGNO collaboration I will have the opportunity to contribute to the measurement of the Migdal effect using the CYGNO prototypes with neutrons. This measurement is crucial for the low mass DM searches, allowing us to safely exploit the Migdal effect to extend the sensitivity of direct detection experiments.

[1] G. G. di Cortona, A. Messina, and S. Piacentini, "Migdal effect and photon bremsstrahlung: improving the sensitivity to light dark matter of liquid argon experiments", JHEP 11 (2020) 034
[2] M. Ibe, W. Nakano, Y. Shoji, and K. Suzuki, "Migdal Effect in Dark Matter Direct Detection Experiments", JHEP 03 (2018) 194