Sparameter in QCD from domain wall fermions

2009/09/27 by Peter A. Boyle, Luigi Del Debbio, Jan Wennekers +2
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-lat

paper · pdf · doi:10.1103/physrevd.81.014504

published as Phys.Rev.D81:014504,2010 · 15 pages, 12 figures

arxiv created 2009/09/27 · openalex publication_date 2010/01/14 · arxiv updated 2010/04/06 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28

Abstract

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 n_f=2+1 flavors of domain wall fermions at a scale of a^\ensuremath-1=2.33 GeV. Relating l₅ to the S parameter in QCD we obtain a value of S(m_H=120 GeV)=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.

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