The LHCb Detector


The LHCb experiment is situated at one of the four points around CERN’s Large Hadron Collider where beams of protons are smashed together, producing an array of different particles.

How does it work?

The aim of the LHCb experiment is to record the decay of particles containing b and anti-b quarks, collectively known as ‘B mesons’. The experiment’s 4,500 tonne detector is specifically designed to filter out these particles and the products of their decay.

Rather than flying out in all directions, B mesons formed by the colliding proton beams (and the particles they decay into) stay close to the line of the beam pipe, and this is reflected in the design of the detector. Other LHC experiments surround the entire collision point with layers of sub-detectors, like an onion, but the LHCb detector stretches for 20 metres along the beam pipe, with its sub-detectors stacked behind each other like books on a shelf.

Plan of the LHCb detector

Each one of LHCb’s sub-detectors specializes in measuring a different characteristic of the particles produced by colliding protons. Collectively, the detector’s components gather information about the identity, trajectory, momentum and energy of each particle generated, and can single out individual particles from the billions that spray out from the collision point.