Abstract
We present a new calculation of the K -> pi semileptonic form factor at zero momentum transfer in domain wall lattice QCD with N-f = 2+1 dynamical quark flavours. By using partially twisted boundary conditions we simulate directly at the phenomenologically relevant point of zero momentum transfer. We perform a joint analysis for all available ensembles which include three different lattice spacings (a = 0.09 - 0.14 fm), large physical volumes (m(pi)L > 3.9) and pion masses as low as 171 MeV. The comprehensive set of simulation points allows for a detailed study of systematic effects leading to the prediction f(+)(K pi)(0) = 0.9670(20)((+18)(-46)), where the first error is statistical and the second error systematic. The result allows us to extract the CKM-matrix element vertical bar V-us vertical bar = 0.2237((+13)(-8)) and confirm first-row CKM-unitarity in the Standard Model at the sub per mille level.
Original language | English |
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Article number | 132 |
Number of pages | 16 |
Journal | Journal of High Energy Physics |
Issue number | 8 |
DOIs | |
Publication status | Published - Aug 2013 |
Keywords / Materials (for Non-textual outputs)
- Lattice QCD
- Quark Masses and SM Parameters
- Kaon Physics
- Standard Model
- TWISTED BOUNDARY-CONDITIONS
- CHIRAL FERMIONS
- LATTICE
- MODEL
- DECAYS