Connecting LHCb to theories of the weak scale

At the CERN LHC, the LHCb experiment will perform a variety of measurements that are sensitive to quantum fluctuations of new particles of TeV mass (about 10-20 times the mass of the weak bosons W and Z) . These involve so-called rare decays of B mesons and related matter-antimatter asymmetries. Particles in the TeV mass range are predicted by all major proposals addressing the origin of the weak scale (mass scale of the W and Z bosons), such as supersymmetry, 'large' extra spacetime dimensions, technicolour, and little higgs theories - generically called 'new physics'. The search for those particles is the main motivation for the LHC experiments, besides the discovery of the Higgs boson. The rare B decays are very sensitive to quantum fluctuations involving any such new particles, because for varying reasons they are strongly suppressed in the absence of new particles, i.e. in what is called the Standard Model of particle physics. (This is what makes them rare.) As such, their measurement provides a very rich source of information on the details of 'beyond-standard model' theories. Many of the LHCb measurements will be possible already in the early stages of the LHCb, when the amount of data taken (technically, 'integrated luminosity') is still small - somewhat of a headstart over the companion experiments ATLAS & CMS, which focus on direct production of new particles. The UK has a very strong experimental involvement in LHCb (one of the strongest of all countries) but comparably very few theoretical activities. To read the fingerprints of the new physics out of the data, however, requires careful theoretical analysis, to separate the 'known', but hard to calculate, 'ordinary' (Standard-Model) effects from the sought-after patterns of what lies beyond. This project involves the systematic and precise application and further development of state-of-the-art methods, based on the heavy-quark expansion for exclusive decays, to the decay modes with the greatest discovery potential: exclusive leptonic, semileptonic, radiative, and two-body hadronic B decays. Thus it provides a valuable and necessary complement to experimental activities in the UK, allowing to make the most of these measurements. As an important part of this project, its investigators will, on a regular basis, meet with experimental UK colleagues and other interested theorists to optimize cooperation and analysis strategies.