Seminarium Teorii Oddziaływań Elementarnych

Waiting eagerly for new discoveries in the LHC era it is easy to forget that also low energy experiments can substantially enrich our knowledge about interactions of elementary particles. For those who did so I will try to show that the low energy experiments can be a valuable source of information, complementary to LHC, provided we can push down both experimental and theoretical uncertainties. In this talk I will concentrate on the muon anomalous magnetic moment ($(g-2)_\mu$), one of the best measured physical observables. The current disagreement between the measured value of $(g-2)_\mu$ and the one calculated within Standard Model, with help of additional low energy data, might be a signal that SMwas just a lengthy break in our voyage towards deeper knowledge. I will report the current experimental and theoretical status of $(g-2)_\mu$. I will show also the main challenges waiting for experimental and theoretical groups to lower the current theory error on the calculation of $(g-2)_\mu$ by factor 4. Only if this requirement is met we will be able to fully profit from the planned $(g-2)_\mu$ measurement at Fermilab and push further the tests of SM and its extensions.