= Zero- and two-fermion vertices of an internally fermionized bosonic string
{title2=$M^2=-4/\alpha',\ -2/\alpha',\ 0$}
In the unprojected polynomial Neveu–Schwarz vertex sector, zero fermion insertions give the usual closed-string tachyon and the massless graviton, two-form and dilaton. Two insertions split into a left-right pair $\psi^i\bar\psi^j e^{ipX}$ of internal weights $(1/2,1/2)$ and a same-chirality current pair of weight one. The first has $M^2=-2/\alpha'$ and 44-squared scalar components. The second requires a bosonic derivative on the opposite side for level matching and gives the two sets of 946 massless gauge vectors. Four-fermion scalar-current products belong to a different insertion count. A chosen global projection may retain a subset, so these operators do not by themselves specify a projected string spectrum.
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