Following the success of the LHC Long-Lived Particle (LLP) Mini-Workshop in May of 2016, the LHC LLP Community -- composed of members of the CMS, LHCb, and ATLAS collaborations as well as theorists, phenomenologists and those interested in LLP searches with auxiliary LHC detectors -- convenes again to address the status and future of LLP searches at the LHC.

This workshop will be one of two workshops devoted to producing an LHC LLP white paper that will be a snapshot of the status of LLP searches at the LHC as of 2017, organized by experimental signature; contain an enumeration of gaps in the coverage of classes of BSM models that can produce LLPs; propose recommendations for triggering strategies for LLPs in ATLAS, CMS, and LHCb; list ideas for new searches for LLPs; and propose a set of recommendations for the presentation of search results to ensure future reinterpretation and recasting.

We will have three days of talks and breakout working sessions that will be geared toward solidifying the structure and components of the white paper, performing phenomenology-level studies for new or existing ideas for LLP searches, and identifying concrete tasks (other studies and writing sections) to be completed during the summer.  To that end, we have converged upon four working groups for the workshop:

WG 1: Simplified models / MC / RECASTing and reinterpretation for LLPs

  • How do we make sure the published searches are optimally useful in the future?  In addition to discussing simplified models for LLPs, this working group will include a hands-on, proof-of-concept recasting of some existing experimental searches that have been archived with the RECAST framework, for a few benchmark model scenarios.

WG 2: Backgrounds for LLP searches

  • What are the challenges of low- or non-standard background searches?  How these have been addressed in the past?  What are the limitations of the current approaches?  What new ideas for better estimates may exist?

WG 3: Triggering strategies and recommended studies for experiments for LLP searches

  • What are the most important, high priority LLP signatures for which triggering strategies don't exist or are known to be sub-optimal?  What recommendation can we as a community make to the experiments for studies that should be done over the summer in support of new triggers?  New, blue-sky ideas mandatory.

WG 4: Dark showers

  • As theorist and ad hoc coordinating committee member Jessie Shelton put it, "one of the major outstanding questions in designing a search program for displaced objects is how to design a simple and flexible basis of models for showering dark sectors."  How do we address this in a more detailed and comprehensive way, and what does this mean for the current searches in the experimental collaborations for this class of models?

For each of the first two days of the workshop, two working groups will proceed in parallel, to be followed by reports on the final day.

The second of the two workshops will take place in October of 2017 and will be centered on finalizing the white paper.

​And although in-person attendance is encouraged, active remote participation -- including for the afternoon breakout working sessions -- will be available via Vidyo.

For information relative to housing and laptop registration, please check

Those without a CERN access card can request one in the registration form.

4/3-006 - TH Conference Room
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