The European Strategy for Particle Physics (ESPP) reflects the vision and presents concrete plans of the European particle physics community for advancing human knowledge in fundamental physics. The ESPP is updated every five-to-six years through a community-driven process. It commences with the submission of specific proposals and other input from the community at large, outlining projects envisioned for the near-, mid-, and long-term future. All submitted contributions are evaluated by the Physics Preparatory Gr…

A bstract A scan of the beam energy across the top quark pair $$ \left(\textrm{t}\overline{\textrm{t}}\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mfenced> <mml:mrow> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:mrow> </mml:mfenced> </mml:math> production threshold is part of the program of future Higgs, top, and electroweak factory projects. In this paper, we provide projections for the achievable precision in the top quark mass ( m t ), widt…

In order to stimulate new engagement and trigger some concrete studies in areas where further work would be beneficial towards fully understanding the physics potential of an $e^+e^-$ Higgs / Top / Electroweak factory, we propose to define a set of focus topics. The general reasoning and the proposed topics are described in this document.

The Higgs self-coupling 𝜆 governs the shape of the Higgs potential and its precise determination is one of the main goals at future colliders. Here we present a new study based on fast simulations at the FCC-hh, assuming √𝑠 = 100 TeV and an integrated luminosity of 30 ab$^{−1}$. The $𝜅_𝜆$ selfcouplingmodifier is determined from double Higgs production in two channels, the 𝑏𝑏𝛾𝛾 and the 𝑏𝑏ℓℓ + 𝐸T𝑚𝑖𝑠𝑠 final states. The 𝑏𝑏𝛾𝛾 drives the precision, down to 3.6%, while the 𝑏𝑏ℓℓ + 𝐸T𝑚𝑖𝑠𝑠achieves an uncertainty of 22%, how…

In this white paper for the 2021 Snowmass process, we give a description of the proposed Future Circular Collider (FCC) project and its physics program. The paper summarizes and updates the discussion submitted to the European Strategy on Particle Physics. After construction of an approximately 90 km tunnel, an electron-positron collider based on established technologies allows world-record instantaneous luminosities at center-of-mass energies from the Z resonance up to tt thresholds, enabling a rich set of fundam…