TY  - CONF
AU  - Fodor, Zoltan
AU  - Krieg, Stefan
AU  - Lippert, Thomas
TI  - Isospin Splittings in the Light Baryon Octet from Lattice QCD+QED at thePhysical Mass Point
VL  - 47
CY  - Jülich
PB  - John von Neumann Institute for Computing
M1  - FZJ-2014-01363
T2  - NIC Series
SP  - 159-168
PY  - 2014
AB  - Electromagnetic effects and the up-down quark mass difference have small but highly important effects on octet baryon masses. A prominent example is the stability of the hydrogen atom against beta decay. Here we report on a calculation1 that includes these effects by adding them to valence quarks in an Nf=2+1 lattice Quantum Chromodynamics calculation based on ensembles with 5 lattice spacings down to 0.054 fm, lattice sizes up to 6 fm, and average up-down quark masses all the way down to their physical value. This large parameter space allows us to gain control over all systematic errors, with the exception of the one associated with neglecting electromagnetism in the sea. We compute the octet baryon isomultiplet mass splittings, as well as the individual contributions from electromagnetism and the up-down quark mass difference. Our results for the total splittings are in good agreement with experiment.
T2  - NIC Symposium 2014
CY  - 12 Feb 2014 - 13 Feb 2014, Jülich (Germany)
Y2  - 12 Feb 2014 - 13 Feb 2014
M2  - Jülich, Germany
LB  - PUB:(DE-HGF)8 ; PUB:(DE-HGF)7
UR  - https://juser.fz-juelich.de/record/151397
ER  -