LHC LLP WG: Long-lived Particles at the LHC

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The LHC Long-lived Particles Working Group (LHC LLP WG) brings together experimentalists and theorists to discuss the physics of new long-lived particles at the LHC. It also covers physics with unconventional experimental signatures. The WG builds on the experience of the LLP LHC Community and, preserving its main scientific objectives, it serves as a formal bridge with the relevant physics groups of the LHC experiments, to streamline the official endorsement of the WG's recommendations to the experiments. The WG will hold open meetings, typically at CERN, complementing the Workshops organized by the LLP LHC Community. The formation of dedicated subgroups, and possible closed meetings (restricted to members of the experimental collaborations), are foreseen. The goals of the working group are to:

  • Facilitate communication between the experimental and theoretical LLP communities.
  • Provide recommendations for benchmark models to be used in LLP interpretations.
  • Develop and/or validate MC tools for event generation (e.g. dark sector showers, library of models).
  • Provide recommendations to experiments on how best to present the results and facilitate reinterpretation of LLP searches.
  • Discuss possible new search directions based on new input from theory and/or experiment.

Working group conveners representing the approved LHC experiments (ATLAS, CMS, FASER, LHCb, and MoEDAL) and the theory community will be appointed by each experiment and the LPCC, respectively. While the WG will focus its activity on items of direct relevance to the LHC physics programme, the participation of the broader LLP community is welcome to its open meetings.


  • WG documents and meeting agendas: see links in the right menu
  • LLP LHC Community white-paper
  • LLP LHC Community web page

WG Topics currently under discussion:

  • tba


  • ATLAS: James Beacham and Sascha Mehlhase
  • CMS: Juliette Alimena and Albert de Roeck
  • FASER: Dave Casper
  • LHCb: Federico Leo Redi and Carlos Vázquez Sierra
  • MoEDAL: James Pinfold
  • Theory: Nishita Desai and José Zurita
  • Reach all through lhc-llpwg-admin@cern.ch