Searching for Physics Beyond the Standard Model

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The ultimate goal of particle physics is to find the theory that unifies all the forces and particles in Nature. A first step has been taken with the unification of the electromagnetic and weak forces into a single "electroweak" force. The Standard Model (SM) of particle physics, which includes the electroweak and the strong forces, successfully explains essentially all known experimental data. Nevertheless, it is clearly not the final theory -- only two of the four forces are unified, and the SM leaves many questions unanswered. Thus, there must be "physics beyond the SM," that is, phenomena that cannot be explained by the SM alone. The search for this "new physics" (NP) is the most important problem facing particle physicists today.There were a number of hints of NP over the past 4-5 years, particularly in b -> s transitions. These were first seen at the "B-factories" BaBar and Belle in various B-meson decays. The hadronic experiments CDF and DØ supported this trend, finding disagreements with the SM predictions in several other B decay modes. Putting all the results together, it appeared that b -> s NP might well be present. Unfortunately, this has not been supported by the LHC: LHCb has remeasured a number of the above quantities, and finds results in agreement with the SM. The bottom line is that there are now fewer hints of NP than there were before.Even so, there are still potential signals of NP in several different areas. There are hints of NP in certain B and D decays, in t-tbar production at hadron colliders, and even in the decay of the Higgs. Furthermore, NP models generally predict the existence of new, exotic particles, which might be produced at the LHC. My research projects touch many of these areas. They all have one common goal: to participate in the search for new physics.