XCC: An X-ray FEL-based ${\hat{I}}^3{\hat{I}}^3$ Collider Higgs Factory

Abstract

This report describes the design of a ${\hat{I}}^3{\hat{I}}^3$ Higgs factory in which 62.8 GeV electron beams collide with 1 keV X-ray free electron laser (XFEL) beams to produce colliding beams of 62.5 GeV photons. The Higgs boson production rate is 34,000 Higgs bosons per $10^7$ second year, roughly the same as the ILC Higgs rate. The electron accelerator is based on cold copper distributed coupling (C${}^3$) accelerator technology. The 0.7 J pulse energy of the XFEL represents a 300-fold increase over the pulse energy of current soft x-ray FEL's. Design challenges are discussed, along with the R\&D to address them, including demonstrators.

27 pages, 16 figures, Contributed to The US Community Study on the Future of Particle Physics (Snowmass 2021)