2008/04/07 by Ian Ellwood
Physics and Astronomy · #hep-th
paper · pdf · doi:10.1088/1126-6708/2008/08/063
published as JHEP 0808:063,2008 · 32 pages, 9 figures
We compute a class of gauge invariant observables for marginal solutions and the tachyon vacuum. In each case we find that the observables are related in a simple way to the closed-string tadpole on a disk with appropriate boundary conditions. We give a sketch of an argument that this result should hold in general using the BRST invariance of the closed string two-point function. Finally, we discuss the analogous set of invariants in the Berkovits superstring field theory.