Worldsheet realization of the Galilean Kalb–Ramond multiplet

Determine whether the multiplet \(\{\chi,\psi_i,E_i,B_{ij}\}\) arises as vertex-operator data deforming the tensionless-string worldsheet coupling, and establish whether the worldsheet \(\mathrm{BMS}_3\) symmetry equals the target-space infinite Galilean conformal algebra.

Background

The Kalb–Ramond field couples directly to the string worldsheet, and the paper identifies the null-reduced four-field multiplet as the natural target-space field content associated with the background. In the tensionless-string regime, such backgrounds can deform the compactified spectrum and are related to worldsheet $\mathrm{BMS}_3$ symmetry.

The paper leaves unresolved whether the complete Galilean multiplet has a worldsheet vertex-operator interpretation and whether the resulting worldsheet symmetry is identical to the target-space infinite-dimensional Galilean conformal algebra.