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HK: Fachverband Physik der Hadronen und Kerne
HK 27: Theorie
HK 27.6: Talk
Wednesday, March 14, 2007, 12:30–12:45, C
Uncertainty bands for chiral extrapolations of lattice QCD results — •Bernhard Musch, Massimiliano Procura, Thomas Hemmert, and Wolfram Weise — Institut für theoretische Physik (T39), TU München, Germany
Lattice QCD calculations are so far performed with up- and down- quark masses typically more than 4 times as large as their physical values. Chiral perturbation theory provides a tool to extrapolate the calculated results and to extract universal low energy constants from them. Here we discuss the error analysis associated with the extrapolation. Statistical errors of the lattice calculations and systematic errors from fixed low energy constants are treated using least squares fits. As a first example, we fit lattice data of the nucleon mass [1] to chiral perturbation theory at order p4 [2].
One way of estimating the theoretical uncertainty is to perform a matching of the theory to a framework with an additional degree of freedom. This is illustrated for the nucleon axial vector coupling constant gA by effectively integrating out the leading contribution from the Δ(1232) isobar [3].
Supported by the DFG Emmy Noether-program.
[1] A. Ali Khan et al., Nucl. Phys. B689 (2004) 175-194
[2] M. Procura et al., Phys. Rev. D73 (2006), 114510
[3] M. Procura, B. Musch, T. Hemmert, W. Weise, hep-lat/0610105.