# Davide Racco

Perimeter Institute for Theoretical Physics

Areas of research:

### Research Interests

I am interested in topics at the crossover between Particle Physics and Cosmology, focusing in particular on dark matter, gravitational waves, Higgs metastability and early universe.
My main area of interest is Dark Matter, and I have worked on various classes of candidates, ranging from WIMPs (particles with masses and interaction strengths comparable to the Standard Model particles, who are currently the target of many experimental searches) to Primordial Black Holes (hypothetical black holes that could have formed in the early history of the Universe) and axions (particles which would also solve the strong CP problem in particle physics). Concerning the production mechanism for Dark Matter, I have been studying gravitational production during inflation, which is a well-motivated and minimal scenario and can guide the identification of benchmarks for direct detection.
I am also very interested in stochastic backgrounds of primordial gravitational waves. Their potential discovery would disclose precious information on the cosmology of the early universe, and the particle content at high energy scales.
I have also worked on the metastability of the Higgs potential: if we extrapolate to high energies the predictions of the Standard Model, the electroweak vacuum appears to be a metastable minimum of the potential. The fact that we live nonetheless in that vacuum today has important implications for the history of the early Universe. As potential observational signatures, I have studied the generation of Primordial Black Holes, of a stochastic background of Gravitational Waves, and a peculiar imprint on the correlation functions of Large Scale Structures.

### Positions Held

- 2014 - 2018 Department of Theoretical Physics, University of Geneva PhD student

### Awards

- Prix Vacheron-Constantin for the best PhD thesis in Physics of the University of Geneva in 2018. Award: watch Vatcheron-Constantin
- Buchalter Cosmology Prize 2018, First Prize, 10 000 USD split among the three authors (J. R. Espinosa, D. Racco, A. Riotto) of the paper "Cosmological Signature of the Standard Model Higgs Vacuum Instability: Primordial Black Holes as Dark Matter", Phys. Rev. Lett. 120 (2018) no.12, 121301, arXiv:1710.11196.

### Recent Publications

- A. Hook, G. Marques-Tavares and D. Racco, Causal gravitational waves as a probe of free streaming particles and the expansion of the Universe, JHEP 02, 117 (2021), arXiv: 2010.03568.
- J. Huang, A. Madden, D. Racco and M. Reig, Maximal axion misalignment from a minimal model, JHEP 10, 143 (2020), arXiv: 2006.07379.
- A. Hook, J. Huang and D. Racco, Minimal signatures of the Standard Model in non-Gaussianities, Phys. Rev. D 101 (2020) no.2, 023519 arXiv: 1908.00019 [hep-ph].
- A. Hook, J. Huang and D. Racco, Searches for other vacua. Part II. A new Higgstory at the cosmological collider, JHEP 01 (2020), 105, arXiv: 1907.10624 [hep-ph].
- G. Franciolini, G. F. Giudice, D. Racco and A. Riotto, Implications of the detection of primordial gravitational waves for the Standard Model, JCAP 1905 (2019) no.05, 022, arXiv: 1811.08118 [hep-ph]
- N. Bartolo, V. De Luca, G. Franciolini, M. Peloso, D. Racco and A. Riotto, Testing primordial black holes as dark matter with LISA, Phys. Rev. D 99 (2019) no.10, 103521, arXiv: 1810.12224 [astro-ph.CO]
- A. Arvanitaki, S. Dimopoulos, M. Galanis, D. Racco, O. Simon and J. O. Thompson, Dark QED from Inflation, arXiv: 2108.04823.

### Seminars

- Gravitational Production of Dark Sectors. Conference "Cosmo from Home 2021" (online)
- Cosmological GW backgrounds: from PBHs to Phase Transitions. LISA Canada Workshop (Canada; online)
- Utilizing the causal spectrum of GWs to probe free streaming particles and the cosmological expansion. Stony Brook University (USA; online)
- Utilizing the causal spectrum of GWs to probe free streaming particles and the cosmological expansion. BSM Pandemic seminar (online)
- Utilizing the causal spectrum of GWs to probe free streaming particles and the cosmological expansion. Tel Aviv University (Israel; online)
- Utilizing the causal spectrum of GWs to probe free streaming particles and the cosmological expansion. Johannes Gutenberg University Mainz (Germany; online)
- Particle Physics, Cosmology and their connection. IQOQI Vienna (Austria)
- Minimal signatures of the Standard Model in cosmological collider physics, University of Maryland (USA)
- Minimal signatures of the Standard Model in cosmological collider physics, CERN (Switzerland)
- Minimal signatures of the Standard Model in cosmological collider physics, University of Geneva (Switzerland)
- Minimal signatures of the Standard Model in cosmological collider physics, University of Amsterdam (Netherlands)
- Minimal signatures of the Standard Model in cosmological collider physics, University of California Berkeley (USA)
- Stochastic backgrounds of Gravitational Waves as an evidence of Primordial Black Holes, Conference "Next Frontiers in the Search for Dark Matter", Galileo Galilei Institute, Firenze (Italy)
- Stochastic backgrounds of Gravitational Waves as an evidence of Primordial Black Holes, Conference Cosmo19, RWTH Aachen University (Germany)
- Cosmological signatures of the SM Higgs instability: Primordial Black Holes and Gravitational Waves, TRIUMF (Canada)
- Cosmological signatures of the SM Higgs instability: Primordial Black Holes and Gravitational Waves, University of Victoria (Canada)
- Cosmological signatures of the SM Higgs instability: Primordial Black Holes and Gravitational Waves, Stanford Institute for Theoretical Physics (USA)
- Cosmological signatures of the SM Higgs instability: Primordial Black Holes and Gravitational Waves, SISSA (Italy)
- PIRSA:18100099, Theoretical Models for Dark Matter: from WIMPs to Primordial Black Holes, 2018-10-26, Particle Physics