Gravitational scattering and radiation in the eikonal approach - Emerging Hawking-like radiation in gravitational scattering beyond the Planck scale

Particle Physics Theory seminar

Gravitational scattering and radiation in the eikonal approach - Emerging Hawking-like radiation in gravitational scattering beyond the Planck scale

• Event time: 2:00pm
• Event date: 15th January 2020
• Speaker: Dr Dimitri Colferai (University of Florence)
• Location: Higgs Centre Seminar Room, Room 4305,

Event details

We generalize the semiclassical treatment of graviton radiation to
gravitational scattering at very large energies
$E >> m_P$ and finite scattering angles $\Theta_s$, so as to approach the
collapse regime. Our basic tool is the
extension of the recently proposed, unified form of radiation to the
Amati-Ciafaloni-Veneziano reduced-action model.
By resumming eikonal scattering diagrams, we
are able to derive the corresponding (unitary) coherent-state operator.
The resulting graviton spectrum turns out to be tuned on the gravitational
radius $R$ for small angles $\Theta_s << 1$ but, for sizeable
angles $\Theta_s \sim 1$ acquires an exponential cutoff of the large frequency
region ($\omega > 1/R$), due to energy conservation, so as to emit a
finite fraction of the total energy. In the approach-to-collapse regime we
find a radiation enhancement due to large tidal forces, so that
the whole energy is radiated off, with a large multiplicity
$<N> \sim Gs >> 1$ and a well-defined frequency cutoff of order $1/R$. The latter
corresponds to the Hawking temperature for a black hole of mass
somewhat smaller than $E$.

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..