Physics Briefing Book: Input for the 2026 update of the European Strategy for Particle Physics

TL;DR

This paper presents the 2026 update of the European Strategy for Particle Physics, outlining community-driven proposals, evaluations, and discussions to guide future fundamental physics research in Europe.

Contribution

It provides a comprehensive input document synthesizing community proposals and evaluations for the 2026 European Strategy update in particle physics.

Findings

Community-driven proposals for future projects

Evaluation process by the Physics Preparatory Group

Broad community discussion at the Symposium

Abstract

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 Group (PPG), and a preliminary analysis is presented at a Symposium meant to foster a broad community discussion on the scientific value and feasibility of the various ideas proposed. The outcomes of the analysis and the deliberations at the Symposium are synthesized in the current Briefing Book, which provides an important input in the deliberations of the Strategy recommendations by the European Strategy Group (ESG).