A detailed study exploiting novel trigger and reconstruction techniques developed to search for Beyond Standard Model (BSM) Long-Lived Particles (LLPs) with very displaced vertices is presented. Building on feasibility studies that have successfully reconstructed Standard Model decays occurring up to 8 m forward of the interaction point in LHCb’s magnet region, the search for LLPs into charged final states exploits LHCb’s unique forward geometry and segmented
tracking system—comprising the Vertex Locator, Upstream Tracker, and SciFi stations—to extend sensitivity into previously inaccessible regions. This proceedings contribution will cover innovative trigger strategies implemented in LHCb’s software trigger for inclusively selecting decays to dimuons displaced up to 8m from the interaction
point, alongside advanced offline selection methods using multivariate analysis methods to robustly suppress background while maintaining high signal efficiency. Preliminary sensitivity estimates
for Dark Higgs 𝐻′ → 𝜇+𝜇− search indicate that these approaches can achieve competitive performance compared to dedicated LLP experiments. Future prospects will also be discussed.
This work aims to provide a comprehensive framework for enhancing LLP discovery potential at LHCb and offers insights that could be beneficial for the broader BSM LLP search community.