Speaker
Description
Nucleon sigma terms quantify the contributions of scalar quark condensates towards the nucleon's mass. Aside from understanding the origins of the various components of the nucleon's mass, these scalar matrix elements strongly affect the magnitude of certain dark matter (WIMP) - nucleon scattering cross sections. Their precise theoretical determination could thus offer input into the experimental detectability of dark matter/beyond the Standard Model (BSM) phenomena. On the lattice, sea quark nucleon sigma terms are represented by disconnected diagrams; in this work, we investigate the use of gradient flow (GF) in calculating the strange and charm nucleon sigma terms, and assess the degree to which GF can improve stochastic noise/systematics in our calculations. A problem particular to gradient flow of scalar matrix elements is the need to flow anti-quarks backwards in time; this can be recast as an "adjoint flow" problem that requires sophisticated hierarchical flow algorithms to achieve optimal speed and memory efficiency, the details of which will also be discussed. We present progress and preliminary calculations of strange and charm sigma terms using a mixed MDWF/HISQ action.