Parity-violating nucleon-nucleon force in the 1/N(c) expansion.

Area of Science:

• Nuclear Physics
• Quantum Chromodynamics (QCD)

Background:

• Experimental studies have confirmed parity violation (PV) in nuclear systems.
• PV is a result of the weak force acting between quarks.

Purpose of the Study:

• To apply the 1/N(c) expansion of QCD to the P-violating, T-conserving component of the nucleon-nucleon (NN) potential.
• To analyze the hierarchy and contributions of different operators to PV in the NN force.

Main Methods:

• Utilized the 1/N(c) expansion of Quantum Chromodynamics (QCD).
• Analyzed the P-violating, T-conserving component of the nucleon-nucleon (NN) potential.
• Investigated operator contributions at various orders of 1/N(c) and sin^2(theta_W).

Main Results:

• Identified two leading-order operators affecting proton-proton (p[over →]p) scattering at order N(c).
• Found additional operators at order N(c)(0)sin^2(theta_W) and O(1/N(c)).
• Demonstrated that pion exchange in the PV NN force is suppressed by 1/N(c) and sin^2(theta_W).

Conclusions:

• The suppression of pion exchange quantitatively explains its nonobservation.
• The large-N(c) hierarchy of other PV NN force mechanisms aligns with phenomenological models.
• Observed PV in p[over →]p scattering is consistent with natural coupling constants, indicating no fine-tuning.