# Kerr black holes and higher-spin amplitudes

#### Kerr black holes and higher-spin amplitudes

- Event time: 2:00pm until 3:00pm
- Event date: 5th October 2022
- Speaker: Paolo Pichini (Uppsala University)
- Location: Higgs Centre Seminar Room, Room 4305, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB

### Event details

Recent years have seen a surge of interest in massive higher-spin scattering amplitudes, motivated by applications to spinning black holes and gravitational wave physics. A special class of amplitudes, known as “minimally coupled”, were used to obtain state-of-the-art results for conservative and radiative observables in binary black-hole systems. In this talk, we ask ourselves the question: why are the “minimally coupled” amplitudes special, and what does that have to do with black holes? Inspired by the higher-spin literature, we find that such amplitudes describe elementary (as opposed to composite) particles, and in particular they obey special high-energy properties required to avoid unitarity violation. Moreover, we compute the classical limit of three-point amplitudes in string theory, focussing on leading Regge states. Despite finding that they do not match black holes, we learn some important lessons on classical limits which are easy to miss in the “minimally coupled’ case. Moreover, we open the way to further exploration of string amplitudes, for instance those involving sub-leading Regge states, and their relation to black holes.

### About Particle Physics Theory seminars

The Particle Physics Theory seminar is a weekly series of talks reflecting the diverse interests of the group. Topics include analytic and numerical calculations based on the Standard Model of elementary particle physics, theories exploring new physics, as well as more formal developments in gauge theories and gravity..