Nucleon axial charge in full lattice QCD
R G Edwards1, G T Fleming, Ph Hägler
1Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA.
Physical Review Letters
|February 21, 2006
Summary
We calculated the nucleon axial charge using full Quantum Chromodynamics (QCD) with pion masses as low as 354 MeV. Our results align with experimental data, showing small finite volume effects.
Area of Science:
- Nuclear Physics
- Quantum Chromodynamics (QCD)
- Hadron Spectroscopy
Background:
- The nucleon axial charge is a fundamental property in nuclear physics.
- Previous lattice QCD calculations were limited by computational resources, restricting the range of pion masses and system sizes that could be studied.
- Understanding the dependence of the nucleon axial charge on pion mass is crucial for testing theoretical models.
Purpose of the Study:
- To calculate the nucleon axial charge as a function of pion mass in full Quantum Chromodynamics (QCD).
- To perform the first lattice QCD calculation with pion masses as low as 354 MeV and volumes up to (3.5 fm)^3.
- To investigate the impact of finite volume effects on the nucleon axial charge.
Main Methods:
- Full lattice Quantum Chromodynamics (QCD) simulations.
- Utilized domain wall valence quarks and improved staggered sea quarks.
- Employed finite volume chiral perturbation theory for constrained fits.
Main Results:
- Presented the first lattice QCD calculation of the nucleon axial charge with pion masses as low as 354 MeV.
- Demonstrated that finite volume effects are small for volumes as large as (3.5 fm)^3.
- Achieved agreement with experimental values within 7% statistical errors after applying a constrained fit.
Conclusions:
- The nucleon axial charge can be reliably calculated in full QCD across a range of pion masses.
- Finite volume effects are manageable at the studied lattice volumes.
- The results provide a significant constraint for theoretical models and future lattice QCD investigations.
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