Relating Hadronic CP Violation to Higher-Twist Distributions.

Area of Science:

• Particle Physics
• Quantum Chromodynamics
• Nuclear Physics

Background:

• The nucleon sigma term is vital for determining CP-odd pion-nucleon couplings.
• Quark chromomagnetic dipole moments are key inputs for these calculations.

Purpose of the Study:

• To establish a connection between the nucleon sigma term and measurable nucleon structure functions.
• To derive a predicted range for the isoscalar quark chromomagnetic dipole moment sigma term.

Main Methods:

• Mapping the isoscalar nucleon sigma term to the third moment of nucleon twist-three chiral-odd distribution functions.
• Surveying existing model calculations and experimental data for these distribution functions.

Main Results:

• Demonstrated that the nucleon sigma term can be mapped to the third moment of specific nucleon distribution functions.
• Derived a predicted range for the isoscalar chromomagnetic dipole moment sigma term based on available data.

Conclusions:

• The study provides a method for experimentally determining the nucleon sigma term.
• The derived range for the isoscalar chromomagnetic dipole moment sigma term offers valuable constraints for future research in CP violation.