I=0 ππ s -wave scattering length from lattice QCD

The ππ scattering length from maximally twisted mass lattice QCD

We calculate the s-wave pion-pion scattering length in the isospin I = 2 channel in lattice QCD for pion masses ranging from 270 MeV to 485 MeV using two flavors of maximally twisted mass fermions at a lattice spacing of 0.086 fm. Additionally, we check for lattice artifacts with one calculation at a finer lattice spacing of 0.067 fm. We use chiral perturbation theory at next-to-leading order t...

The ππ S - wave scattering lengths July 11 , 2000

We match the known chiral perturbation theory representation of the ππ scattering amplitude to two loops with a phenomenological description that relies on the Roy equations. On this basis, the corrections to Wein-berg's low energy theorems for the S-wave scattering lengths are worked out to second order in the expansion in powers of the quark masses. The resulting predictions, a 0 0 = 0.220 ± ...

The ππ S - wave scattering lengths July 24 , 2000

We match the known chiral perturbation theory representation of the ππ scattering amplitude to two loops with a phenomenological description that relies on the Roy equations. On this basis, the corrections to Wein-berg's low energy theorems for the S-wave scattering lengths are worked out to second order in the expansion in powers of the quark masses. The resulting predictions, a 0 0 = 0.220 ± ...

K→(ππ)(I=2) decay amplitude from lattice QCD.

We report on the first realistic ab initio calculation of a hadronic weak decay, that of the amplitude A(2) for a kaon to decay into two π mesons with isospin 2. We find ReA(2)=(1.436±0.063(stat)±0.258(syst))10(-8) GeV in good agreement with the experimental result and for the hitherto unknown imaginary part we find ImA(2)=-(6.83±0.51(stat)±1.30(syst))10(-13) GeV. Moreover combining our result ...

Charmed Meson Scattering from Lattice QCD