We have computed the SU(2) Low Energy Constant l5 and the mass splitting between charged and neutral pions from a lattice QCD simulation of nf = 2 + 1 flavors of Domain Wall Fermions at a scale of a-1 = 2.33GeV. Relating l5 to the S parameter in QCD we obtain a value of S(mH=120GeV) = 0.42(7), in agreement with previous determinations. Our result can be compared with the value of S from electroweak precision data which constrains strongly interacting models of new physics like Technicolor. This work in QCD serves as a test for the methods to compute the S parameter with Domain Wall Fermions in theories beyond the Standard Model. We also infer a value for the pion mass splitting in agreement with experiment.
|Number of pages||8|
|Journal||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|Publication status||Published - 14 Jan 2010|