We present results for the ∆I = 3/2 K → ππ decay amplitude computed using lattice quantum chromodynamics. The calculation is performed using 2 + 1 flavours of domain wall fermion and the Iwasaki gauge action modified by the dislocation suppressing determinant ratio, on a lattice volume of 32^3 × 64 × 32 at lattice spacing a^−1 = 1.364 GeV. The resulting valence pion mass is mπ = 142.11 MeV, and the kaon mass is mK = 505.5 MeV. A total of 146 configurations are analysed, giving ReA2 = 1.381(46)stat (258)syst × 10−8 GeV and ImA2 = −6.54(46)stat (120)syst × 10^−8 GeV. The experimental results for ReA0 and ReA2 and ǫ′/ǫ are combined with this lattice result for ImA2 to give ImA0 /ReA0 = −1.61(28) × 10^−4. We also present results from a second calculation where both the ∆I = 1/2 and ∆I = 3/2 K → ππ decay amplitudes are calculated. This calculation is performed using 2 + 1 flavours of domain wall fermions with the Iwasaki gauge action and a lattice size of 16^3 × 32 × 16. Since the evaluation of A0 is technically challenging, this first ever determination of A0 is performed at threshold with a heavy pion mass of mπ ∼ 420 MeV. The results are Re(A0) = 3.80(82) × 10^−7 GeV and Im(A0) = −2.5(2.2) × 10^−11 GeV.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:568867 |
| Date | January 2012 |
| Creators | Goode, Elaine |
| Contributors | Sachrajda, Christopher |
| Publisher | University of Southampton |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://eprints.soton.ac.uk/346839/ |
Page generated in 0.0127 seconds