Highlights from the LHCb Experiment

The LHCb experiment [1] is a single-arm forward spectrometer covering the pseudorapidity (η) range from 2 to 5. It was optimized for the study of hadrons containing b or c quarks. Therefore, LHCb has excellent vertexing, tracking, and particle identification capabilities [2]. On top of that, LHCb provides the unique opportunity for the LHC to operate in a fixed target mode, thanks to the System for Measuring Overlap with Gas (SMOG). During the LHC Run 2, LHCb collected various proton–nucleus and nucleus–nucleus collisions. In its collider mode, the exploitation of proton– lead (pPb), lead–proton (Pbp), and proton–proton (pp) collisions leads to stringent constraints on hadron production and transport in nuclear environment in high-energy collisions. The lead–lead (PbPb) collisions collected in 2015 and 2018 show the saturation of the LHCb tracking system in the most central collisions (up to 60% centrality). Despite this limitation, the PbPb collisions remain relevant for analyses focusing on ultra-peripheral and peripheral collisions. Complementary to the collider mode, LHCb exploits SMOG to perform physics runs since 2015. Using dedicated LHC fills, LHCb has a unique opportunity to investigate cosmic ray and heavy-ions physics in the high Björken-x region.