I am currently a Postdoctoral Fellow at SITP (Stanford Institute for Theoretical Physics) since Oct 2021.
Before, I was a Postdoctoral Fellow at Perimeter Institute for Theoretical Physics (Waterloo, Canada) between Oct 2018 and Sep 2021.
I obtained my PhD degree from the University of Geneva under the supervision of Antonio Riotto in Sep 2018.
During my PhD I spent six months (Apr-Sep 2017) at IFAE in the Universitat Autònoma de Barcelona to collaborate with José Ramón Espinosa.
During my undergraduate studies I was enrolled in the University of Padova and in the Galilean School of Higher Education, and I completed the Master thesis in 2014 under the supervision of Fabio Zwirner and Andrea Wulzer.

Honors & Awards

  • Prix Vacheron-Constantin for the best PhD thesis in Physics of the University of Geneva in 2018, University of Geneva (June 2019)
  • Buchalter Cosmology Prize 2018, First Prize for the paper Phys. Rev. Lett. 120 (2018) no.12, 121301, Buchalter Cosmology Prize (January 2019)
  • Prize for the best 10 Bachelor students from the University of Padova graduated in 2012, Association "Amici dell'Università di Padova" (November 2013)

Professional Education

  • Postdoctoral Fellow, Perimeter Institute for Theoretical Physics, Particle Physics and Cosmology (2021)
  • Ph.D., University of Geneva (Switzerland), Cosmology and Particle Physics (2018)
  • Diploma, School of Excellence, Galilean School of Higher Education of Padova (Italy), Natural Sciences (2014)
  • M.Sc. in Physics, University of Padova (Italy), Theoretical Physics (2014)
  • Summer Student, CERN (Switzerland), Experimental Particle Physics (2012)
  • B.Sc. in Physics, University of Padova (Italy), Physics (2012)

Stanford Advisors

Current Research and Scholarly Interests

I am interested in topics at the crossover between Particle Physics and Cosmology, focusing in particular on dark matter, gravitational waves, non-Gaussianities, 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.

All Publications

  • Freeze-in dark matter perturbations are adiabatic Journal of Cosmology and Astroparticle Physics Racco, D., Riotto, A. 2023
  • Precision cosmology with primordial GW backgrounds in presence of astrophysical foregrounds Journal of Cosmology and Astroparticle Physics Racco, D., Poletti, D. 2023
  • Dark QED from inflation JOURNAL OF HIGH ENERGY PHYSICS Arvanitaki, A., Dimopoulos, S., Galanis, M., Racco, D., Simon, O., Thompson, J. O. 2021
  • Causal gravitational waves as a probe of free streaming particles and the expansion of the Universe JOURNAL OF HIGH ENERGY PHYSICS Hook, A., Marques-Tavares, G., Racco, D. 2021
  • Maximal axion misalignment from a minimal model JOURNAL OF HIGH ENERGY PHYSICS Huang, J., Madden, A., Racco, D., Reig, M. 2020
  • Minimal signatures of the standard model in non-Gaussianities PHYSICAL REVIEW D Hook, A., Huang, J., Racco, D. 2020; 101 (2)
  • Searches for other vacua. Part II. A new Higgstory at the cosmological collider JOURNAL OF HIGH ENERGY PHYSICS Hook, A., Huang, J., Racco, D. 2020
  • Dark Matter benchmark models for early LHC Run-2 Searches: Report of the ATLAS/CMS Dark Matter Forum PHYSICS OF THE DARK UNIVERSE Abercrombie, D., Akchurin, N., Akilli, E., Alcaraz Maestre, J., Allen, B., Gonzalez, B., Andrea, J., Arbey, A., Azuelos, G., Azzi, P., Backovic, M., Bai, Y., Banerjee, S., Beacham, J., Belyaev, A., Boveia, A., Brennan, A., Buchmueller, O., Buckley, M. R., Busoni, G., Buttignol, M., Cacciapaglia, G., Caputo, R., Carpenter, L., Castro, N., Ceballos, G., Cheng, Y., Chou, J., Cortes Gonzalez, A., Cowden, C., D'Eramo, F., De Cosa, A., De Gruttola, M., De Roeck, A., De Simone, A., Deandrea, A., Demiragli, Z., DiFranzo, A., Doglioni, C., du Pree, T., Erbacher, R., Erdmann, J., Fischer, C., Flaecher, H., Fox, P. J., Fuks, B., Genest, M., Gomber, B., Goudelis, A., Gramling, J., Gunion, J., Hahn, K., Haisch, U., Harnik, R., Harris, P. C., Hoepfner, K., Hoh, S., Hsu, D., Hsu, S., Iiyama, Y., Ippolito, V., Jacques, T., Ju, X., Kahlhoefer, F., Kalogeropoulos, A., Kaplan, L., Kashif, L., Khoze, V. V., Khurana, R., Kotov, K., Kovalskyi, D., Kulkarni, S., Kunori, S., Kutzner, V., Lee, H., Lee, S., Liew, S., Lin, T., Lowette, S., Madar, R., Malik, S., Maltoni, F., Martinez Perez, M., Mattelaer, O., Mawatari, K., McCabe, C., Megy, T., Morgante, E., Mrenna, S., Moon, C., Narayanan, S. M., Nelson, A., Novaes, S. F., Padeken, K., Pani, P., Papucci, M., Paulini, M., Paus, C., Pazzini, J., Penning, B., Peskin, M. E., Pinna, D., Pazzini, J., Penning, B., Peskin, M. E., Pinna, D., Procura, M., Qazi, S. F., Racco, D., Re, E., Riotto, A., Rizzo, T. G., Roehrig, R., Salek, D., Pineda, A., Sarkar, S., Schmidt, A., Schramm, S., Shepherd, W., Singh, G., Soffi, L., Srimanobhas, N., Sung, K., Tait, T. P., Theveneaux-Pelzer, T., Thomas, M., Tosi, M., Trocino, D., Undleeb, S., Vichi, A., Wang, F., Wang, L., Wang, R., Whallon, N., Worm, S., Wu, M., Wu, S., Yang, H., Yang, Y., Yu, S., Zaldivar, B., Zanetti, M., Zhang, Z., Zucchetta, A. 2020; 27
  • Testing primordial black holes as dark matter with LISA PHYSICAL REVIEW D Bartolo, N., De Luca, Franciolini, G., Peloso, M., Racco, D., Riotto, A. 2019; 99 (10)
  • Implications of the detection of primordial gravitational waves for the Standard Model JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS Franciolini, G., Giudice, G. F., Racco, D., Riotto, A. 2019
  • Primordial black holes from Higgs vacuum instability: avoiding fine-tuning through an ultraviolet safe mechanism EUROPEAN PHYSICAL JOURNAL C Espinosa, J. R., Racco, D., Riotto, A. 2018; 78 (10): 806


    We have recently proposed the idea that dark matter in our universe is formed by primordial black holes generated by Standard Model Higgs fluctuations during inflation and thanks to the fact that the Standard Model Higgs potential develops an instability at a scale of the order of 10 11 GeV. In this sense, dark matter does not need any physics beyond the Standard Model, although the mechanism needs fine-tuning to avoid the overshooting of the Higgs into the dangerous AdS vacuum. We show how such fine-tuning can be naturally avoided by coupling the Higgs to a very heavy scalar with mass ≫ 10 11 GeV that stabilises the potential in the deep ultraviolet, but preserving the basic feature of the mechanism which is built within the Standard Model.

    View details for DOI 10.1140/epjc/s10052-018-6274-2

    View details for Web of Science ID 000446575400002

    View details for PubMedID 31708681

    View details for PubMedCentralID PMC6821662

  • A cosmological signature of the SM Higgs instability: gravitational waves JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS Espinosa, J. R., Racco, D., Riotto, A. 2018
  • Cosmological Signature of the Standard Model Higgs Vacuum Instability: Primordial Black Holes as Dark Matter PHYSICAL REVIEW LETTERS Espinosa, J. R., Racco, D., Riotto, A. 2018; 120 (12): 121301


    For the current central values of the Higgs boson and top quark masses, the standard model Higgs potential develops an instability at a scale of the order of 10^{11}  GeV. We show that a cosmological signature of such instability could be dark matter in the form of primordial black holes seeded by Higgs fluctuations during inflation. The existence of dark matter might not require physics beyond the standard model.

    View details for DOI 10.1103/PhysRevLett.120.121301

    View details for Web of Science ID 000428167200005

    View details for PubMedID 29694085

  • On dark matter interactions with the Standard Model through an anomalous Z ' JOURNAL OF HIGH ENERGY PHYSICS Ismail, A., Katz, A., Racco, D. 2017
  • Complementarity of DM searches in a consistent simplified model: the case of Z ' JOURNAL OF HIGH ENERGY PHYSICS Jacques, T., Katz, A., Morgante, E., Racco, D., Rameez, M., Riotto, A. 2016
  • The 750 GeV diphoton excess, dark matter and constraints from the IceCube experiment JOURNAL OF HIGH ENERGY PHYSICS Morgante, E., Racco, D., Rameez, M., Riotto, A. 2016
  • Scanning of the supersymmetry breaking scale and the gravitino mass in supergravity JOURNAL OF HIGH ENERGY PHYSICS Farakos, F., Kehagias, A., Racco, D., Riotto, A. 2016
  • The halo Boltzmann equation JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS Biagetti, M., Desjacques, V., Kehagias, A., Racco, D., Riotto, A. 2016
  • Simplified models for dark matter searches at the LHC PHYSICS OF THE DARK UNIVERSE Abdallah, J., Araujo, H., Arbey, A., Ashkenazi, A., Belyaev, A., Berger, J., Boehm, C., Boveia, A., Brennan, A., Brooke, J., Buchmueller, O., Buckley, M., Busoni, G., Calibbi, L., Chauhan, S., Daci, N., Davies, G., De Bruyn, I., De Jong, P., De Roeck, A., de Vries, K., Del Re, D., De Simone, A., Di Simone, A., Doglioni, C., Dolan, M., Dreiner, H. K., Ellis, J., Eno, S., Etzion, E., Fairbairn, M., Feldstein, B., Flaecher, H., Feng, E., Fox, P., Genest, M., Gouskos, L., Gramling, J., Haisch, U., Harnik, R., Hibbs, A., Hoh, S., Hopkins, W., Ippolito, V., Jacques, T., Kahlhoefer, F., Khoze, V. V., Kirk, R., Korn, A., Kotov, K., Kunori, S., Landsberg, G., Liem, S., Lin, T., Lowette, S., Lucas, R., Malgeri, L., Malik, S., McCabe, C., Mete, A., Morgante, E., Mrenna, S., Nakahama, Y., Newbold, D., Nordstrom, K., Pani, P., Papucci, M., Pataraia, S., Penning, B., Pinna, D., Polesello, G., Racco, D., Re, E., Riotto, A., Rizzo, T., Salek, D., Sarkar, S., Schramm, S., Skubic, P., Slone, O., Smirnov, J., Soreq, Y., Sumner, T., Tait, T. P., Thomas, M., Tomalin, I., Tunnell, C., Vichi, A., Volansky, T., Weiner, N., West, S. M., Wielers, M., Worm, S., Yavin, I., Zaldivar, B., Zhou, N., Zurek, K. 2015; 9-10: 8-23
  • Robust collider limits on heavy-mediator Dark Matter JOURNAL OF HIGH ENERGY PHYSICS Racco, D., Wulzer, A., Zwirner, F. 2015