UNC-CH Physics and Astronomy Colloquium
Huey-Wen Lin, Michigan State
“Probing New Physics with Lattice QCD”
There is a worldwide race to find new-physics signatures both on the high-energy frontier, such as at the LHC, and on the intensity frontier, at many smaller experiments looking at electric dipole moments, for dark matter, and many more. Precision knowledge about nucleons is becoming increasingly critical to to either determine Standard-Model backgrounds or to interpret the signatures predicted for particles beyond the Standard Model. Lattice QCD is an ideal theoretical method to for determining these nonperturbative QCD quantities.
In this talk, I will review the progress and prospects for lattice QCD as a bridge between theory and precision experiments.
In the first part, I discuss how we overcame a long-standing obstacle, and for the first time in lattice-QCD, were able to directly calculate the Bjorken-x dependence of the parton distribution functions (PDFs).
This breakthrough opens an exciting new frontier to improve the dominant uncertainty in the global analysis of PDFs used in Higgs production cross sections.
Then, I discuss how lattice nucleon coupling calculations are now entering a precision era, where calculations are done at the physical pion mass with fully controlled systematics. This was first achieved by the Precision Neutron-Decay Matrix Element (PNDME) collaboration.
PNDME’s high-quality precision nucleon inputs can be applied to searches for new physics; I give examples for neutron beta decay and the neutron electric dipole moment.