School Seminar Program

Capture of dark matter in compact stars

Dr Giorgio Busoni
Department of Fundamental and Theoretical Physics, RSPhys, ANU
& ARC Centre of Excellence for Dark Matter Particle Physics

Neutron stars harbour matter under extreme conditions, providing a unique testing ground for fundamental interactions. Dark matter can be captured by neutron stars via scattering, where kinetic energy is transferred to the star. This can have a number of observational consequences, such as the heating of old neutron stars to infra-red temperatures. Previous treatments of the capture process have employed various approximation or simplifications.

For leptonic Targets, a relativistic description is essential. Regarding Baryons, we outline two important effects that are missing from most evaluations of the dark matter capture rate in neutron stars. As dark matter scattering with nucleons in the star involves large momentum transfer, nucleon structure must be taken into account via a momentum dependence of the hadronic form factors.

In addition, due to the high density of neutron star matter, we should account for nucleon interactions rather than modeling the nucleons as an ideal Fermi gas. Properly incorporating these effects is found to suppress the dark matter capture rate by up to three orders of magnitude.

Dr. Giorgio Busoni obtained his Ph.D. in Theoretical Particle Physics in 2015 at the International School for Advanced Studies (SISSA), in Trieste, Italy. During his Ph.D., he was a visitor at the University of Geneva and CERN. After that, he held Research Assistant appointments at The University of Melbourne, between 2015 and 2018, under the supervision of Prof. N. F. Bell, and at the Max Planck Institute for Nuclear Physics in Heidelberg, between 2018 and 2021, Germany, under the supervision of Prof. M. Lindner. His research focuses on Dark Matter phenomenology and beyond the Standard Model Physics. As a Research Fellow in the Research of Physics, ANU, Dr. Giorgio Busoni is part of the ARC Centre of Excellence for Dark Matter Particle Physics.

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