The Large Hadron Collider (LHC) is the world’s most energetic proton-proton collider, located at the CERN laboratory on the Swiss-French border just outside of Geneva. It was designed and built to discover physics Beyond the Standard Model (BSM), either through direct detection of new massive particles at the CMS and/or ATLAS experiments, or through the indirect detection at the LHCb experiment.
The LHCb Experiment at CERN is a general purpose detector at the LHC, and is primarily designed to search for physics Beyond the Standard Model (BSM) in the decays of hadrons containing beauty (b) and charm (c) quarks. Just as the Standard Model W and Z bosons participate in the weak decays of heavy quarks, new heavy BSM particles — assuming they exist and couple to the standard model particles — would also contribute to the decays rate of b and c quarks. The greatest sensitivity is expected to occur in b or c-hadron decays that involve quantum loops. Precision measurements of those b- and c-hadron decays that must proceed through quantum loops provide an alternative way (to direct detection) to uncover hints of BSM physics.
Unlike the CMS and ATLAS experiments at the LHC, LHCb covers the forward region, from about 15-350 mrad. Due to the production dynamics of beauty and antibeauty quarks at the LHC, a large fraction of the beauty-antibeauty pairs that are produced fall into this narrow cone. This enables a number of important measurements at LHCb — mainly those involving CP Violation— that would otherwise not be possible.
The main objective of LHCb is to uncover New Physics, and many LHCb analyses are focused on just. Topics include, but are not limited to:
- B and Bs mixing;
- CP violation and CP violating phases
- Rare/forbidden decays of b- and c-hadrons
- Lepton flavor universality/violation
- Dark photons
- Majorana neutrino searches
Many other interesting areas of physics are explored as well, many which provide test of, or constraints on QCD or other aspects of the Standard Model. A sampling of some of these areas include:
- Spectroscopy: Search for and discovery of new hadronic states, both conventional baryons and mesons, as well as multi-quark states (tetraquarks and pentaquarks).
- Precision measurements of the properties of b and c-hadrons, such as lifetimes, masses and branching fractions.
- Numerous studies that probe the strong force (QCD), including quarkonium
- Electroweak physics: Studies of the W and Z bosons, and top quarks
- Heavy Ion collisions
A full listing of LHCb’s physics publications can be found here.
To read about some analyses that SU faculty and students have undertaken, read the Plain English summaries.