### John Negele (MIT)

#### Understanding the Structure of Nucleons using Lattice QCD

I will describe for non-specialists the use of lattice QCD, numerical solution of QCD on a discrete space-time lattice, to calculate the the properties of protons and neutrons, the basic building blocks of nearly all the matter in the observed universe, from first principles. I will then describe recent success[1], after decades of effort, in obtaining agreement with experiment for the charge radius, magnetization radius, magnetic moment, and fraction of momentum arising from quarks. I will also discuss calculation of electromagnetic form factors [2], exploration of the origin of the nucleon spin, prediction[3] of scalar and tensor charges needed in planning searches for physics beyond the Standard Model in cold neutron decay experiments, and future challenges

References:

[1] Nucleon Structure from Lattice QCD Using a Nearly Physical Pion Mass

J. R. Green, M. Engelhardt, S. Krieg, J. W. Negele, A. V. Pochinsky, S. N. Syritsyn arXiv:1209.1687, 2012

[2] Nucleon Scalar and Tensor Charges from Lattice QCD with Light Wilson Quarks J. R. Green, J. W. Negele, A. V. Pochinsky, S. N. Syritsyn, M. Engelhardt, S. Krieg Phys Rev D.86.114509, 2012, arXiv:1206.4527

[3] Nucleon electromagnetic form factors from lattice QCD using a nearly physical pion mass J. R. Green, J. W. Negele, A. V. Pochinsky, S. N. Syritsyn, M. Engelhardt, S. Krieg arXiv:1404.4029, 2014