Scalar Bremsstrahlung in Gravity-Mediated Ultrarelativistic Collisions

TL;DR

This paper investigates scalar bremsstrahlung in ultra-relativistic gravity-mediated collisions with extra dimensions, revealing a strong Lorentz factor dependence and interference effects in the emitted radiation.

Contribution

It provides a detailed analysis of scalar radiation spectra and angular distribution, highlighting the impact of extra dimensions and interference effects in ultra-relativistic collisions.

Findings

Scalar radiation energy is enhanced by a power of the Lorentz factor depending on extra dimensions.

Destructive interference occurs between direct radiation and $ ext{Phi-phi-graviton}$ interaction in specific frequency regimes.

The spectral and angular distributions of emitted scalar radiation are characterized across different dimensions.

Abstract

Classical bremsstrahlung of a massless scalar field $\Phi$ is studied in gravity mediated ultra-relativistic collisions with impact parameter $b$ of two massive point particles in the presence of $d$ non-compact or toroidal extra dimensions. The spectral and angular distribution of the scalar radiation are analyzed, while the total emitted $\Phi-$energy is found to be strongly enhanced by a $d-$dependent power of the Lorentz factor $\gamma$. The direct radiation amplitude from the accelerated particles is shown to interfere destructively (in the first two leading ultra-relativistic orders) with the one due to the $\Phi-\Phi-graviton$ interaction in the frequency regime $\gamma/b\lesssim \omega \lesssim \gamma^2/b$ in all dimensions.