U.S. Higgs Factory Consortium Input to the 2025 update of the European Strategy for Particle Physics

Abstract

This white paper responds to the request by the European Strategy Group (ESG) to submit national inputs as part of the European Strategy for Particle Physics Update (ESPPU). It focuses on CERNs future collider options and provides strong support for FCC-ee as its preferred next major flagship project. The paper follows the ECFA guidelines, responding explicitly to item 3, and is supported by recent developments following the 2023 P5 Report. It also outlines the U.S. scientific and engineering expertise including potential technical contributions to a future Higgs Factory.