arXiv subjects
Publications and source records attributed to Valery Telnov.
This report on Photon Colliders briefly reviews three main issues: physics motivation, possible parameters and technical feasibility, plans of works and international cooperation. New scheme of laser optics at the interaction region is described which can drastically (at least by one order) reduce the cost of the laser system.
It is very likely that in 3-4 years the construction of one or two linear colliders with c.m.s energy up to 0.5--1.5 TeV will be started. Besides e^+e^- collisions, linear colliders give a unique possibility to study gamma-gamma and gamma-electron interactions at energies and luminosities comparable to those in e^+e^- collisions. High energy photons for gamma-gamma and gamma-electron collisions can be obtained using laser backscattering. These types of collisions considerably increase the physics potential of linear colliders for relatively a small incremental cost. This report briefly reviews the physics goals and possible parameters of gamma-gamma colliders.
In this review we consider three important applications of lasers in high energy physics: gamma gamma, gamma electron colliders, laser cooling, positron production. These topics are actual now due to plans of construction linear e+e-, e-e-, gamma-gamma, gamma-e colliders with energies 0.3--1 TeV. High energy photons for gamma-gamma, gamma-e collisions can be obtained using laser backscattering. These types of collisions considerably increase physics potential of linear colliders. Very low emittance of electron beams required for achieving ultimate gamma-gamma luminosity can be obtained using a laser cooling of electron beams. Combining a laser-electron Compton scattering with subsequent conversion of these photons to e+e- pairs on the target (it can be a laser target) one can get a nice source of polarized positron. In this paper, we briefly consider these subjects with emphasis on underlying physics of photon-electron interactions.
Using the laser backscattering method at future TeV linear colliders one can obtain gamma-gamma and electron-gamma colliding beams (photon colliders) with the energy and luminosity comparable to that in e+e- collisions. Now this option is included to conceptual designs of linear colliders. This paper (talk at the conference on nonlinear optics) is a short introduction to this field with an emphasis on required lasers which can be used both for e -> gamma conversion and for preparation of electron beams (photoguns, laser cooling), some interesting nonlinear QED effects in a strong field which apply restrictions on parameters of photon colliders are discussed.
Last two years were very important in history of a photon colliders. This option is included now in conceptual design reports of the NLC, JLC and TESLA/SBLC projects. All the designs foresee two interaction regions: one for e+e- and the second for gamma-gamma, gamma-e and e^-e^- collisions. This paper is focused on three aspects: 1) arguments for photon colliders; 2) parameters of current projects; 3) ultimate luminosities and energies, new ideas. Recent studies have shown that the main collision effect - coherent pair creation - is suppressed at photon colliders with the energy (2E < 2 TeV) due to the beam repulsion, and one can achieve, in principle, the gamma-gamma luminosity exceeding 10^{35} cm^-2s^-1. The required electron beams with very small emittances can be obtained, for example, using a laser cooling of electron beams. This new method requires a laser with a power by one order of magnitude higher than that required for the ``conversion'' of electrons to photons. Such lasers are not available today, but hopefully they will appear by the time when linear colliders will be built. High energy gamma-gamma, gamma-e colliders with the luminosity comparable to that in e^+e^- collisions are beyond the competition in study of many phenomena of particle physics.
A photon collider luminosity and its energy are determined by the parameters of an electron-electron linear collider (energy, power, beam emittances) and collision effects. The main collision effect is the coherent e+e- pair creation. At low energies (2E < 0.5 - 1 TeV) this process is suppressed due to repulsion of electron beams. In this region gamma-gamma luminosity above 10^{35} cm-2 s-1 is possible (10^{33} is sufficient). At higher energies the limited average beam power and coherent pair creation restrict the maximum energy of photon colliders (with sufficient luminosity) at 2E ~ 5 TeV. Obtaining high luminosities requires the development of new methods of production beams with low emittances such as a laser cooling.