A new era in particle physics is about to begin. As the world’s most powerful particle accelerator — the Large Hadron Collider (LHC) at CERN, just outside Geneva — prepares to switch on later this year, excitement is mounting about what researchers will discover from the proton–proton collisions that will take place at the 27 km-circumference machine. Many expect new particles to be created, perhaps ending the 30-year reign of the Standard Model of particle physics. Adding to the excitement, recent results from Fermilab and the Stanford Linear Accelerator Center (SLAC) in the US, and the KEK laboratory in Japan suggest that the LHC will reap a particularly bountiful harvest.

But the LHC’s first discoveries might come from an unexpected quarter: the LHCb experiment. Unlike the mammoth “general purpose” detectors ATLAS and CMS, which will search for particles, such as the Higgs boson, produced directly in the proton–proton collisions, LHCb is a smaller experiment devoted to the study of B-mesons. These particles, which comprise a bottom quark or antiquark plus one other quark with a different “flavour”, only exist for about a trillionth of a second before decaying into lighter particles. But subtle quantum effects called loops, in which virtual particles are temporarily created by borrowing energy from the vacuum, can influence the behaviour of B-mesons and give researchers a handle on particles that are too heavy to be produced directly.

In the June issue of Physics World, Tim Gershon tells how the LHCb may be the first experiment at the LHC to glimpse new physics, and may make a major discovery within the first year of data-collection.

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