Proton lifetime bounds from chirally symmetric lattice QCD

Understand

We present results for the matrix elements relevant for proton decay in Grand Unified Theories (GUTs).

• The calculation is performed at a fixed lattice spacing a^{-1}=1.73(3) GeV using 2+1 flavors of domain wall fermions on lattices of size 16^3\times32 and 24^3\times64 with a fifth dimension of length 16.
• We use the indirect method which relies on an effective field theory description of proton decay, where we need to estimate the low energy constants, \alpha = -0.0112(25) GeV^3 and \beta = 0.0120(26) GeV^3.
• We relate these low energy constants to the proton decay matrix elements using leading order chiral perturbation theory.