Ghost number 2The NSNS 3-form field strength should correspond to:It turns out that the linearized SUGRA equations of motion are not satisfied, because. However, the derivatives of
are all zero:
therefore this is a “zero mode effect”.This is a puzzle. Most likely, the zero modes are not correctly reproduced in the current version of the pure spinor formalism. The disagreement in the zero mode sector was discussed in arxiv:1005.0049 and arxiv:1203.0677. It would be useful to explicitly trace the connection between the nonzero
and the “non-physical” vertex found in those papers.