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K→(ππ)(I=2) decay amplitude from lattice QCD
T Blum1, P A Boyle, N H Christ
1Physics Department, University of Connecticut, Storrs, Connecticut 06269-3046, USA.
Physical Review Letters
|May 1, 2012
Summary
This study presents the first realistic ab initio calculation of kaon decay into two pions. The results for the amplitude A(2) agree with experiments and provide crucial data for understanding CP violation.
Area of Science:
- * Subatomic Physics
- * Quantum Chromodynamics
- * Particle Physics
Background:
- * Hadronic weak decays, specifically kaon to two pions, are crucial for testing the Standard Model.
- * Previous calculations lacked the precision to fully address CP violation parameters.
- * Lattice Quantum Chromodynamics (QCD) is a key tool for non-perturbative calculations in particle physics.
Purpose of the Study:
- * To perform the first realistic ab initio calculation of the hadronic weak decay amplitude A(2) for kaon to two pions.
- * To determine both the real and imaginary parts of A(2) with high precision.
- * To investigate the implications for direct CP violation and the Electroweak Penguin contribution.
Main Methods:
- * Utilized ab initio lattice QCD calculations to simulate the hadronic weak decay process.
- * Employed advanced computational techniques to achieve realistic precision.
- * Combined calculated and experimental values to derive key CP violation parameters.
Main Results:
- * Calculated ReA(2) = (1.436 ± 0.063(stat) ± 0.258(syst)) × 10⁻⁸ GeV, matching experimental data.
- * Determined the previously unknown ImA(2) = -(6.83 ± 0.51(stat) ± 1.30(syst)) × 10⁻¹³ GeV.
- * Derived ImA(0)/ReA(0) = -1.63(19)(stat)(20(syst)) × 10⁻⁴ and Re(ε'/ε)(EWP) = -(6.52 ± 0.49(stat) ± 1.24(syst)) × 10⁻⁴.
Conclusions:
- * This calculation marks a significant milestone for lattice QCD in studying weak decays.
- * The results provide a quantitative understanding of CP violation in kaon decays.
- * Offers exciting prospects for future precision tests of the Standard Model.
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