Mandate of the Physics Beyond Colliders Study Group (Revised January 2021)



The PBC study was launched in 2016 to explore the scientific potential of the CERN accelerator complex and infrastructure for projects complementary to high-energy frontier colliders, and to provide input to the European Particle Physics Strategy Update (EPPSU). The EPPSU deliberations were supportive of PBC studies, and recommended an enhanced collaboration of CERN with other laboratories in Europe and beyond. As a consequence, the CERN Directorate wishes to maintain the PBC study group as a long-term activity, with a mandate and organization updated to take into account the EPPSU recommendations.

Scientific goal

The main goal of the Study Group remains to explore the opportunities offered by CERN’s unique accelerator complex, its scientific and technical infrastructure, and its know-how in accelerator and detector science and technology, to address today’s outstanding questions in particle physics through initiatives that complement the goals of the main experiments of the Laboratory’s collider programme. Examples of physics objectives include dedicated experiments for studies of rare processes and searches for feebly interacting particles. The physics objectives also include projects aimed at addressing fundamental particle physics questions using the experimental techniques of nuclear, atomic, and astroparticle physics, as well as emerging technologies such as quantum sensors, that would benefit from the contribution of CERN competences and expertise. The study group will primarily investigate, and, where appropriate, provide support to, projects expected to be sited at CERN. The study group may also examine ideas and provide initial support for contributions to projects external to CERN. The study group is also expected to act as a central forum for exchanges between the PBC experimental community and theorists for assessment of the physics reach of the proposed projects in a global landscape.


The group will continue to be led by three coordinators representing the scientific communities of accelerator, experimental, and theoretical particle physics. The coordination team reports to the CERN Directorate. The coordinators will update the PBC working group structure to reflect the updated PBC mandate and input from the community. The PBC study group will act as CERN’s initial portal for new ideas which may come in spontaneously or through specific calls launched by the PBC coordination team. The group will facilitate and support an initial evaluation of the relevance and technical feasibility of the ideas in a global context, and will regularly inform the CERN scientific committees (INTC, SPSC or LHCC) about their findings. Where appropriate, oversight of PBC studies will be passed to the relevant CERN scientific committee once they are adequately mature for scrutiny and review of possible implementation.