Berkovits, Nathan [UNESP]2013-09-302014-05-202013-09-302014-05-202008-01-01Journal of High Energy Physics. Trieste: Int School Advanced Studies, n. 1, p. 27, 2008.1126-6708http://hdl.handle.net/11449/24340After adding a pair of non-minimal fields and performing a similarity transformation, the BRST operator in the pure spinor formalism is expressed as a conventional-looking BRST operator involving the Virasoro constraint and (b, c) ghosts, together with 12 fermionic constraints. This BRST operator can be obtained by gauge-fixing the Green-Schwarz superstring where the 8 first-class and 8 second-class Green-Schwarz constraints are combined into 12 first-class constraints. Alternatively, the pure spinor BRST operator can be obtained from the RNS formalism by twisting the ten spin-half RNS fermions into five spin-one and five spin-zero fermions, and using the SO(10)/U(5) pure spinor variables to parameterize the different ways of twisting. GSO(-) vertex operators in the pure spinor formalism are constructed using spin fields and picture-changing operators in a manner analogous to Ramond vertex operators in the RNS formalism.27engsuperstrings and heterotic stringstopological stringsArtigo10.1088/1126-6708/2008/01/065WOS:000252983400012Acesso restrito