Oct 11, 2018 3:45 pm - Nielsen Hall 170 - Colloquium
Doreen Wackeroth - University at Buffalo – SUNY
News from the Precision Frontier at the Large Hadron Collider

Despite the enormous success of the Standard Model (SM) of particle

physics in describing all experimentally observed electromagnetic,

weak and strong interactions of the constituents of matter, it is

generally accepted that the SM is merely a low-energy approximation to

a more fundamental theory. The last missing ingredient of the SM, the

Higgs boson, was recently discovered at the CERN Large Hadron Collider

(LHC) exhibiting SM-like properties, so that the spectrum of particles

in the SM is now complete. Now we hope that the LHC will reveal what

lies beyond the SM in form of the emergence of new, non-SM particles

and/or interactions.


Key ingredients in this endeavor are precision calculations of SM

observables and of signatures of new physics models, including their

SM backgrounds. Properties and interactions of the mediators of the

weak force (W and Z bosons), of the heaviest quark (top quark), and of

the newly discovered Higgs bosons are being measured at an

unprecedented level of precision. Well-defined precision observables,

such as the recent measurement of the mass of the W boson at the LHC,

provide indirect access to new physics. New particles and interactions

can leave their trace in these SM observables through their virtual

presence in quantum loops. I will present examples of these precision

measurements at the LHC, their potential for discovery, and of the

tremendous, ongoing theory effort in providing the necessary

high-precision predictions.