Project Overview

Over the past several years, I have initiated a numerical study of N=1 supersymmetric Yang-Mills (SYM) theory for the gauge group SU(2). The simulations used a chiral fermion lattice formulation known as domain wall fermions (DWFs)--a five-dimensional lattice formulation of fermions, where the physical (approximately) chiral modes are realized as states bound to the boundaries of the extra fifth dimension. For these past studies, configuration generation and measurements were performed on 83x8 and 163x32 lattices using the New York Blue (BlueGene/L) and QCDOC supercomputers at Brookhaven National Laboratory and Columbia University.

Because these numerical studies were exploratory in nature, it was important to establish benchmarks to guide future investigation, and to assess the degree to which the fermion discretization was correctly reproducing the desired continuum low energy four dimensional physics of N=1 SYM. Quantities of interest included:

Qualitative features of the simulation results provided strong evidence that the correct continuum physics was being reproduced. However, for the parameters under consideration, I concluded that the simulations were not sufficiently close to the chiral limit to reliably perform chiral and SUSY limit extrapolations. This was due to unexpectedly large residual chiral symmetry breaking attributed to the fermion discretization (the errors achieved in chiral extrapolations were around 25%).

Using my 2009-2010 USQCD allocation of 4.92M QCDOC node-hours, supplemented with computer time on New York Blue, I intend to perform a new set of numerical simulations at a single (and possibly a second) lattice spacing using an improved lattice action known as the Auxiliary Determinant (AuxDet) DWF action. In the context of lattice QCD, this new action has resulted in significant reduction of residual chiral symmetry breaking. Similar favorable results are expected for N=1 SYM, and would allow for a drastic reduction in chiral limit extrapolation errors.