High energy particle colliders: past 20 years, next 20 years and beyond

Abstract

Particle colliders for high energy physics have been in the forefront of scientific discoveries for more than half a century. The accelerator technology of the collider has progressed immensely, while the beam energy, luminosity, facility size and the cost have grown by several orders of magnitude. The method of colliding beams has not fully exhausted its potential but its pace of progress has greatly slowed down. In this paper we very briefly review the method and the history of colliders, discuss in detail the developments over the past two decades and the directions of the R&D toward near future colliders which are currently being explored. Finally, we make an attempt to look beyond the current horizon and outline the changes in the paradigm required for the next breakthroughs. Content: 1. Introduction, colliders of today a. The method b. Brief history of the colliders, beam physics and key technologies c. Past 20 years -achievements and problems solved 2. Next 20 years: physics, technologies and machines a. LHC upgrades and lower energy colliders b. Post-LHC energy frontier lepton colliders: ILC, CLIC, Muon Collider 3. Beyond 2030's: new methods and paradigm shift a. Possible development of colliders in the resource-limited world b. Future technologies: acceleration in microstructures, in plasma and in crystals c. Luminosity limits 4. Conclusions

Ultimate colliders for particle physics: Limits and possibilities

“…There is only one such option known now: super-dense plasma as in, e.g., crystals 9 , but that excludes protons because of nuclear interactions and leaves us with muons as the particles of choice. Acceleration of muons (instead of electrons or hadrons) in crystals or carbon nanotubes with charge carrier density ∼10 22 cm −3 has the promise of the maximum theoretical accelerating gradients of 1-10 TeV/m allowing to envision a compact 1 PeV linear crystal muon collider 1 . High luminosity can not be expected for such a facility if the beam power P is limited (e.g., to keep the total facility site power to some affordable level of P ∼100MW).…”

Experience with crystals at Fermilab accelerators

“…Initial outlook for ultimate future energy frontier collider facility with beam energies 20-100 times the LHC energy indicates promising potential of a compact 1 PeV linear crystal collider based on acceleration of muons (instead of electrons or hadrons) in super-dense plasma of crystals was 18 . Nanostructures, such as carbon nanotubes (CNTs) can also be used offering a number of advantages over crystals for a proof-ofprinciple experiment (wider channels and weaker dechanneling; possibility to accept broader beams using nanotube ropes, easier 3D control of beam bending over greater lengths) 19 .…”

On the feasibility of a pulsed 14 TeV c.m.e. muon collider in the LHC tunnel

“…A next generation energy-frontier particle physics facility must provide an energy reach beyond that of the LHC, with the potential for the discovery of new physics, and still be affordable within future available budgets [1,2,3]. The proposed pulsed 14 TeV c.m.e.…”