Limitation on the luminosity of e+e- storage rings due to beamstrahlung

TL;DR

This paper demonstrates that beamstrahlung imposes a fundamental luminosity limit on high-energy e+e- storage rings, affecting their feasibility for future colliders and favoring linear colliders at energies above 150 GeV.

Contribution

It provides a theoretical analysis of beamstrahlung effects on storage-ring luminosity limits at energies above 140 GeV, including new scaling laws and comparisons with linear colliders.

Findings

Beamstrahlung causes particle loss, limiting luminosity at high energies.

Luminosity scales as R/E^{13/3} for fixed synchrotron radiation power.

Linear colliders become more advantageous than storage rings above 150 GeV.

Abstract

Particle loss due to the emission of single energetic beamstrahlung photons in beam collisions is shown to impose a fundamental limit on storage-ring luminosities at energies greater than 2E~140 GeV for head-on collisions and 2E~40 GeV for crab-waist collisions. Above these threshold energies, the suppression factor due to beamstrahlung scales as 1/E^{4/3}, and for a fixed power of synchrotron radiation, the luminosity L is proportional to R/E^{13/3}, where R is the collider radius. For 2E > 150 GeV, both collision schemes have similar luminosity limits. The luminosities attainable at storage-ring and linear-collider (LC) 2E=240 GeV Higgs factories are comparable; at higher energies, LCs are preferable. This conference paper is based on my recent PRL publication [1], supplemented with additional comments on linac-ring e+e- colliders and ring e+e- colliders with charge compensation (four-beam collisions).