# L63: PROTON-NEUTRON MASS DIFFERENCE

**Category:** library_prompt | **Kernel:** PHAT v1.27.5 | **Status:** PENDING

## Prompt

PROTON-NEUTRON MASS DIFFERENCE
m_p - m_n ~ -1.293 MeV (neutron heavier). Using the isospin breaking from L46 and EM correction: m_p - m_n = (m_u - m_d) * factor + EM correction. Compute from v1.27.5 parameters. Compare to PDG. #SuperGrokTOE #ProtonNeutron #IsospinBreaking