Extracting Scattering Parameters using the Isospin Chemical Potential
Michael Buchoff
Lawrence Livermore National Laboratory
Hadronic scattering mediated through the strong interaction has been an area
of great interest for both theory and experiment. Recently, lattice QCD
calculations of scattering processes from first principles have seen
remarkable progress, including multiple calculations of two-pion scattering
lengths that agree with experiment to within a few percent. However, there
exists a certain class of scattering processes, such as pion-nucleon
scattering, that contain annihilation diagrams, which are prohibitively
expensive to simulate on the lattice. In this talk, I will present a method
to extract certain parameters from this class of scattering processes by
employing an isospin chemical potential, which can be simulated on the
lattice as a result of its positive-definite fermion determinant.