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Kaon B parameter from improved staggered fermions in N(f)=2+1 QCD
Taegil Bae1, Yong-Chull Jang, Chulwoo Jung
1Korea Institute of Science and Technology Information, Daejeon, 305-806, South Korea.
Physical Review Letters
|September 26, 2012
Summary
We calculated the kaon B parameter (B(K)) using lattice quantum chromodynamics (QCD) with improved staggered fermions. Our precise result, B(K)=0.727±0.004(stat)±0.038(syst), advances fundamental physics understanding.
Area of Science:
- High Energy Physics
- Quantum Chromodynamics
- Hadron Spectroscopy
Background:
- The kaon B parameter (B(K)) is crucial for understanding weak interactions and CP violation.
- Lattice QCD provides a non-perturbative method to calculate fundamental parameters in particle physics.
Purpose of the Study:
- To compute the kaon B parameter (B(K)) with high precision using lattice QCD.
- To reduce systematic uncertainties in B(K) calculations through improved methods and finer lattice spacings.
Main Methods:
- Utilizing improved staggered valence and sea fermions (N(f)=2+1 flavors) from the MILC Collaboration.
- Employing multiple lattice spacings down to a≈0.045 fm to control discretization errors.
- Performing chiral and continuum extrapolations with SU(2) staggered chiral perturbation theory.
Main Results:
- Obtained a precise value for the kaon B parameter: B(K)=0.727±0.004(stat)±0.038(syst).
- Identified truncated (one-loop) matching factors as the dominant source of systematic error.
Conclusions:
- The calculated B(K) value provides a significant constraint for Standard Model extensions.
- Further refinements in matching factor calculations are needed to reduce systematic uncertainties.
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