Speaker
Dr
Stefan Meinel
(Massachusetts Institute of Technology)
Description
We present results for the disconnected contributions to light-quark nucleon form factors and generalized form factors at a pion mass of approximately 300 MeV. The calculations are performed with clover fermions in a large volume, and the disconnected quark loops are evaluated using the hierarchical probing method. We compare the behavior of hierarchical probing with the traditional noise method for a wide range of observables. A large reduction of variance is observed for the electromagnetic form factors. For these form factors, we are able to clearly resolve nonzero disconnected light-quark contributions for the first time. We find that the ratio of disconnected to connected contributions to the proton electromagnetic form factors is of order 0.5%.
Primary author
Dr
Stefan Meinel
(Massachusetts Institute of Technology)
Co-authors
Prof.
Andreas Stathopoulos
(College of William and Mary)
Dr
Andrew Pochinsky
(Massachusetts Institute of Technology)
Dr
Jeremy Green
(University of Mainz)
Jesse Laeuchli
(College of William and Mary)
Prof.
John Negele
(Massachusetts Institute of Technology)
Prof.
Kostas Orginos
(College of William and Mary)
Michael Engelhardt
(New Mexico State University)
Dr
Sergey Syritsyn
(RIKEN-BNL Research Center)
Dr
Stefan Krieg
(Forschungszentrum Juelich GmbH/Wuppertal University)
