White Paper: AWAKE, Plasma Wakefield Acceleration of Electron Bunches for Near and Long Term Particle Physics Applications

Abstract

Plasma-based accelerators have made remarkable progress over the last two decades. Their unique characteristics make them tools that can revolutionize fields of science and applications. AWAKE takes advantage of the availability of high-energy, relativistic proton bunches to drive large amplitude wakefields (∼GV/m) in a single plasma over distances sufficient to produce hundreds of GeV to TeV electron bunches. Hundreds of GeV bunches with O(10 9 ) electrons could replace current electron sources based on the generation of secondary particles, thereby extending in the next decade the reach of dark photon search experiments. Collisions between O(50 GeV ) electrons and protons with LHC energy would allow studying low x processes, processes with high cross-section, making studies interesting even with low luminosity.Bunches of TeV electrons with TeV protons would allow for center-of-mass energy of 9 TeV, 30 times higher than at HERA. Such a very-high energy ep/eA collider, would be smaller and give access to physics beyond the reach of colliders using other electron acceleration schemes.Based on experimental and numerical simulation results obtained in the early phase of AWAKE (Run 1), that demonstrated the basic features of the accelerator scheme, we developed a clear science roadmap that, at the beginning of the next decade (end of Run 2), would put AWAKE in a position to propose first particle physics experiments with 50-200 GeV electron bunches. This raodmap based on a plasma for self-modulation of the p + bunch and one for acceleration of the electron bunch, and on external injection in order to preserve the quality of the bunch that is accelerated (charge, energy spread, emittance). The roadmap includes:• 2021-22: Demonstrating seeding of the self-modulation (SM) of the p + bunch with an electron bunch;• 2023-25: Introducing a step in the plasma density at a location during the SM growth for wakefields to maintain large amplitude over long plasma distances;

The science case for an intermediate energy advanced and novel accelerator linear collider facility

“…With sufficient science motivation, one possible IEF that could be considered is a 20-100 GeV center-of-mass energy ANA-based linear lepton collider. In what follows we focus on the science case for an IEF since the necessary R&D effort as well as potential near term applications of ANAs are outlined in other white papers submitted to Snowmass21 [6][7][8]. The goal of the proposed IEF is to both carry out particle physics measurements in the 20-100 GeV ranges, as well as to serve as a ANA demonstrator facility.…”

“…Electron beams have been accelerated up to 8 GeV over 20 cm at the Lawrence Berkeley National Laboratory using a PW laser pulse propagating in a plasma channel [5]. A discussion of the status of ANA research as well as the necessary avenues for achieving progress in this field may be found in the whitepapers "Linear collider based on laser-plasma accelerators", "AWAKE, Plasma Wakefield Acceleration of Electron Bunches for Near and Long Term Particle Physics Applications", and "Near Term Applications driven by Advanced Accelerator Concepts" submitted to Snowmass21 [6][7][8].…”