### Abstract

We compute classical gravitational bremsstrahlung from the gravitational scattering of two massless particles at leading order in the (centre of mass) deflection angle . The calculation, although non-perturbative in the gravitational constant, is surprisingly simple and yields explicit formulae - in terms of multidimensional integrals - for the frequency and angular distribution of the radiation. In the range , the GW spectrum behaves like , is confined to cones of angular sizes (around the deflected particle trajectories) ranging from to , and exactly reproduces, at its lower end, a well-known zero-frequency limit. At the radiation is confined to cones of angular size of order resulting in a scale-invariant () spectrum. The total efficiency in GW production is dominated by this 'high frequency' region and is formally logarithmically divergent in the UV. If the spectrum is cutoff at the limit of validity of our approximations (where a conjectured bound on GW power is also saturated), the fraction of incoming energy radiated away turns out to be at leading logarithmic accuracy.

Original language | English (US) |
---|---|

Article number | 125012 |

Journal | Classical and Quantum Gravity |

Volume | 33 |

Issue number | 12 |

DOIs | |

State | Published - May 17 2016 |

### Fingerprint

### Keywords

- frequency and angular spectrum
- gravitational radiation
- ultra-relativistic collisions

### ASJC Scopus subject areas

- Physics and Astronomy (miscellaneous)

### Cite this

*Classical and Quantum Gravity*,

*33*(12), [125012]. https://doi.org/10.1088/0264-9381/33/12/125012

**Gravitational radiation from massless particle collisions.** / Gruzinov, Andrei; Veneziano, Gabriele.

Research output: Contribution to journal › Article

*Classical and Quantum Gravity*, vol. 33, no. 12, 125012. https://doi.org/10.1088/0264-9381/33/12/125012

}

TY - JOUR

T1 - Gravitational radiation from massless particle collisions

AU - Gruzinov, Andrei

AU - Veneziano, Gabriele

PY - 2016/5/17

Y1 - 2016/5/17

N2 - We compute classical gravitational bremsstrahlung from the gravitational scattering of two massless particles at leading order in the (centre of mass) deflection angle . The calculation, although non-perturbative in the gravitational constant, is surprisingly simple and yields explicit formulae - in terms of multidimensional integrals - for the frequency and angular distribution of the radiation. In the range , the GW spectrum behaves like , is confined to cones of angular sizes (around the deflected particle trajectories) ranging from to , and exactly reproduces, at its lower end, a well-known zero-frequency limit. At the radiation is confined to cones of angular size of order resulting in a scale-invariant () spectrum. The total efficiency in GW production is dominated by this 'high frequency' region and is formally logarithmically divergent in the UV. If the spectrum is cutoff at the limit of validity of our approximations (where a conjectured bound on GW power is also saturated), the fraction of incoming energy radiated away turns out to be at leading logarithmic accuracy.

AB - We compute classical gravitational bremsstrahlung from the gravitational scattering of two massless particles at leading order in the (centre of mass) deflection angle . The calculation, although non-perturbative in the gravitational constant, is surprisingly simple and yields explicit formulae - in terms of multidimensional integrals - for the frequency and angular distribution of the radiation. In the range , the GW spectrum behaves like , is confined to cones of angular sizes (around the deflected particle trajectories) ranging from to , and exactly reproduces, at its lower end, a well-known zero-frequency limit. At the radiation is confined to cones of angular size of order resulting in a scale-invariant () spectrum. The total efficiency in GW production is dominated by this 'high frequency' region and is formally logarithmically divergent in the UV. If the spectrum is cutoff at the limit of validity of our approximations (where a conjectured bound on GW power is also saturated), the fraction of incoming energy radiated away turns out to be at leading logarithmic accuracy.

KW - frequency and angular spectrum

KW - gravitational radiation

KW - ultra-relativistic collisions

UR - http://www.scopus.com/inward/record.url?scp=84971657506&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84971657506&partnerID=8YFLogxK

U2 - 10.1088/0264-9381/33/12/125012

DO - 10.1088/0264-9381/33/12/125012

M3 - Article

VL - 33

JO - Classical and Quantum Gravity

JF - Classical and Quantum Gravity

SN - 0264-9381

IS - 12

M1 - 125012

ER -