Tree-Level Mixing of the Long (2,2) Singlet in AdS3 x S3 x T4 RR Supergravity

We determine the tree-level mixing matrix of the long (2,2) singlet in five global two-particle Kaluza–Klein channels of type IIB supergravity on AdS3 × S3 × T4 with pure Ramond–Ramond flux and zero torus momentum. Three scalar–spinor logarithms fix the mixed entries. The four-spinor logarithms, including the fermion-corrected tensor duality contact, and a separate triplet projection fix the fermionic block. The eigenvalues of the matrix shifting each conformal weight in units of 1/N are −18, −3, −3, −3, −6/5. Its second moment gives this sector's one-loop double logarithms, including those with external fermionic pairs. This deposit contains the manuscript PDF (version 4), the LaTeX source archive, the README, and the complete Supplemental Material ZIP containing the symbolic inputs, Python/SymPy programs, output records, fixed-sector truncation notes and reproduction instructions.