Photon collider at TESLA

TL;DR

Photon colliders based on laser backscattering at TESLA could significantly enhance high-energy physics research, offering higher cross sections and event rates, with recent technological advances making their implementation feasible.

Contribution

This paper reviews the potential of photon colliders at TESLA, highlighting recent progress and feasible laser technologies for their realization.

Findings

Gamma-gamma luminosity can reach one-third of e+e- luminosity.

Photon colliders offer higher cross sections than e+e- collisions.

Technological solutions like optical cavities and laser systems are feasible for TESLA.

Abstract

High energy photon colliders (gamma-gamma, gamma-electron) based on backward Compton scattering of laser light is a very natural addition to e+e- linear colliders. In this report we consider this option for the TESLA project. Recent study has shown that the horizontal emittance in the TESLA damping ring can be further decreased by a factor of four. In this case the gamma-gamma luminosity luminosity in the high energy part of spectrum can reach (1/3)L_{e+e-}. Typical cross sections of interesting processes in gamma-gamma collisions are higher than those in e+e- collisions by about one order of magnitude, so the number of events in gamma-gamma collisions will be more than that in e+e- collisions. Photon colliders can, certainly, give additional information and they are the best for the study of many phenomena. The main question is now the technical feasibility. The key new element in photon colliders is a very powerful laser system. An external optical cavity is a promising approach for the TESLA project. A free electron laser is another option. However, a more straightforward solution is ``an optical storage ring (optical trap)'' with diode pumped solid state laser injector which is today technically feasible. This paper briefly reviews the status of a photon collider based at TESLA, its possible parameters and existing problems.