https://doi.org/10.1140/epjc/s10052-018-6311-1
Regular Article - Theoretical Physics
New infra-red enhancements in 4-derivative gravity
1
Theoretical Physics Department, CERN, Geneva, Switzerland
2
Dipartimento di Fisica dell’Università di Pisa and INFN, Pisa, Italy
3
National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
* e-mail: alberto.salvio@roma2.infn.it
Received:
3
September
2018
Accepted:
4
October
2018
Published online:
20
October
2018
4-Derivative gravity provides a renormalizable theory of quantum gravity at the price of introducing a physical ghost, which could admit a sensible positive-energy quantization. To understand its physics, we compute ghost-mediated scatterings among matter particles at tree-level, finding a new power-like infra-red enhancement typical of 4-derivative theories, that we dub ‘ghostrahlung’. Super-Planckian scatterings get downgraded to Planckian by radiating hard gravitons and ghosts, which are weakly coupled and carry away the energy.
© The Author(s), 2018