Interrelation of superconducting and antiferromagnetic gaps in High-T-c compounds: A test case for the SO(5) theory

Recent angle resolved photoemission data, which found evidence for a d-wave -like modulation of the antiferromagnetic gap, suggest an intimate interrel ation between the antiferromagnetic insulator and the superconductor with i ts LI-wave gap. It is shown here that a projected SO(5) theory, which expli citly takes the Mott-Hubbard gap into account, correctly describes the obse rved gap characteristics. Specifically, it accounts for the order of magnit ude difference between the antiferromagnetic gap modulation and the superco nducting gap and is also consistent with the gap dispersion.