The CMS Collaboration

The CMS Collaboration is an organization of academic institutions that have cooperated to build and operate the CMS detector. Collaborating scientists at member institutions analyze the data recorded by CMS, exploiting the physics potential of the Large Hadron Collider at CERN. The structure of the CMS Collaboration, its objectives, means of governance, and the rights and obligations of the collaborating institutes,are defined in a formal constitution. Adherence to the constitution is confirmed by Memoranda of Understanding (MoU), signed by Funding Agencies on behalf their respective institutes, and by CERN as the host laboratory. A key principle of our collaboration is an equitable sharing of the workload associated with the construction, operation, maintenance and upgrade of the detector, whilst allowing all CMS members freedom to pursue science exploitation activities of their choice.

Types of Membership

There are three ways in which institutes can participate in CMS. An institute with FULL MEMBERSHIP profits from being a member of a leading international scientific community, by taking part in technology development, data processing and computing, and physics analysis. For institutes wishing to join the collaboration, but whose resources initially preclude full membership, two other categories are defined, both offering a meaningful but more restricted role. New institutions may join for a time-limited period as a COOPERATING INSTITUTE, allowing them to gain experience of a global collaboration as a precursor to full membership. Alternatively, ASSOCIATED INSTITUTES collaborate on technical aspects such as engineering or computing, for an indefinite period, to the mutual benefit of both parties.

For more info please consult the "How to join CMS" and "Full Member Responsibility" official documents and contact the Engagement Office


Institutions with full membership have a correspondingly full set of rights and obligations within the Collaboration. In particular, they are represented within the Collaboration Board, the supreme decision- making body where major issues are discussed and decided by voting. Every institution with full membership has equal voting rights. In addition, collaborators at institutes with full membership:

  • Have the opportunity to sign all CMS physics and technical publications

  • Are eligible to take leadership and coordination roles across all CMS activities.

Obligations on full member institutes include:

  • Financial contributions towards the operational and upgrade costs of the detector, within the framework of maintenance and operations (M&O) resources and the CMS upgrade project

  • Practical contributions towards the operation of the experiment, within the framework of Experimental Physics Responsibility (EPR) credits.

    Financial obligations may be met in part through in-kind contributions of deliverables in technical areas, though direct contributions for operational costs, common funds and upgrade projects are expected. The level of the required financial and operational contributions depends on the number of PhD-level or equivalent authors associated with the institute. More details are given in a separate document (‘Full Member Responsibilities in CMS’).


Cooperating Institute status, which has a limited duration, allows new institutions intending to join CMS to gain experience with analyzing physics data and using collaboration tools, while working toward full membership. The maximum duration of this arrangement is expected to be around five years. Members of Cooperating Institutes:

  • Contribute to specific and well-defined technical projects and physics analyses, enabling them to gain experience

  • Sign papers to which they make a direct contribution

  • Can participate in Collaboration Board discussions via the Team Leader, but without the right to vote.

    There is no specific financial contribution requirement associated with Cooperating Institute status, though institutes are expected to cover the direct cost of their own participation. The financial and EPR contributions made during this phase of membership are accounted for when obtaining full membership.


Associated Institute status is the means of formally recognizing a group supplying particular expertise in engineering or computing, but which is not necessarily interested in participating in physics analysis. Members of Associated Institutes:

  • Contribute to specific and well-defined technical projects, including engineering or computing

  • May use their CMS activities as a context for education of students in these aspects, or to attract new funding for projects in which they participate

  • Are not expected to become involved in physics analyses.

  • Can participate in Collaboration Board discussions via the Team Leader, but without the right to vote.

There is no specific financial contribution requirement associated with Associated Institute status, though institutes are expected to cover the direct cost of their own participation.

Procedure for joining CMS

In the first instance, an institution wishing to join the collaboration should contact the CMS Spokesperson to express its interest. Discussions can initially proceed through informal contacts, but at some point, the official joining procedure must be launched via a formal letter (Letter of Intent). The Spokesperson will then bring the application to the attention of the CMS Management Board to explore how the new collaborators may be integrated into the collaboration and consult with the relevant CMS Regional Representative. A letter of acknowledgement will be sent by the spokesperson to the applying institute, following which the CMS Resources Manager will request information regarding the viability and means of the necessary financial contributions. The institute must then reply, acknowledging its understanding of the required financial and operational contributions, and confirming its readiness to meet them, via a letter signed by the Institute Director.

Following this exchange of information, the Chair of the Collaboration Board, the Spokesperson and the Resources Manager will seek to meet the applicants and a representative of the relevant Funding Agency, to discuss in detail the terms of entry.

The Team Leader of the prospective new collaborating institute will be invited to give a short presentation at a Collaboration Board meeting, which should provide information on the composition and interests of the research group, their relevant experience, and the proposed contribution to collaboration activities. After the presentation, the Collaboration Board will discuss the application, and any questions raised will be passed to the applicants for clarification. A final decision on admission will be made at a subsequent Collaboration Board meeting via a formal vote.