20 research outputs found
The One-loop Open Superstring Massless Five-point Amplitude with the Non-Minimal Pure Spinor Formalism
We compute the massless five-point amplitude of open superstrings using the
non-minimal pure spinor formalism and obtain a simple kinematic factor in pure
spinor superspace, which can be viewed as the natural extension of the
kinematic factor of the massless four-point amplitude. It encodes bosonic and
fermionic external states in supersymmetric form and reduces to existing
bosonic amplitudes when expanded in components, therefore proving their
equivalence. We also show how to compute the kinematic structures involving
fermionic states.Comment: 38 pages, harvmac TeX, v2: fix typo in (4.2) and add referenc
Some Superstring Amplitude Computations with the Non-Minimal Pure Spinor Formalism
We use the non-minimal pure spinor formalism to compute in a super-Poincare
covariant manner the four-point massless one and two-loop open superstring
amplitudes, and the gauge anomaly of the six-point one-loop amplitude. All of
these amplitudes are expressed as integrals of ten-dimensional superfields in a
"pure spinor superspace" which involves five coordinates covariantly
contracted with three pure spinors. The bosonic contribution to these
amplitudes agrees with the standard results, and we demonstrate identities
which show how the and tensors naturally emerge from
integrals over pure spinor superspace.Comment: 20 pages, harvmac te
Pure Spinor Superspace Identities for Massless Four-point Kinematic Factors
Using the pure spinor formalism we prove identities which relate the
tree-level, one-loop and two-loop kinematic factors for massless four-point
amplitudes. From these identities it follows that the complete supersymmetric
one- and two-loop amplitudes are immediately known once the tree-level
kinematic factor is evaluated. In particular, the two-loop equivalence with the
RNS formalism (up to an overall coefficient) is obtained as a corollary.Comment: 10 pages, harvmac TeX. v2: Updated affiliation and Report-no
Type I Supergravity Effective Action from Pure Spinor Formalism
Using the pure spinor formalism, we compute the tree-level correlation
functions for three strings, one closed and two open, in N=1 D=10 superspace.
Expanding the superfields in components, the respective terms of the effective
action for the type I supergravity are obtained. All terms found agree with the
effective action known in the literature. This result gives one more
consistency test for the pure spinor formalism.Comment: 25 page
DDF Construction and D-Brane Boundary States in Pure Spinor Formalism
Open string boundary conditions for non-BPS D-branes in type II string
theories discussed in hep-th/0505157 give rise to two sectors with integer (R
sector) and half-integer (NS sector) modes for the combined fermionic matter
and bosonic ghost variables in pure spinor formalism. Exploiting the manifest
supersymmetry of the formalism we explicitly construct the DDF (Del Giudice, Di
Vecchia, Fubini) states in both the sectors which are in one-to-one
correspondence with the states in light-cone Green-Schwarz formalism. We also
give a proof of validity of this construction. A similar construction in the
closed string sector enables us to define a physical Hilbert space in pure
spinor formalism which is used to project the covariant boundary states of both
the BPS and non-BPS instantonic D-branes. These projected boundary states take
exactly the same form as those found in light-cone Green-Schwarz formalism and
are suitable for computing the cylinder diagram with manifest open-closed
duality.Comment: 37 pages, typos corrected, some organisational changes mad
Note About Classical Dynamics of Pure Spinor String on AdS_5 x S_5 Background
We will discuss some properties of the pure spinor string on the AdS_5 x S_5
background. Using the classical Hamiltonian analysis we will show that the
vertex operator for the massless state that is in the cohomology of the BRST
charges describes on-shell fluctuations around AdS_5 x S_5 background.Comment: 26. pages, added references, v2:corrected typo
Towards Pure Spinor Type Covariant Description of Supermembrane -- An Approach from the Double Spinor Formalism --
In a previous work, we have constructed a reparametrization invariant
worldsheet action from which one can derive the super-Poincare covariant pure
spinor formalism for the superstring at the fully quantum level. The main idea
was the doubling of the spinor degrees of freedom in the Green-Schwarz
formulation together with the introduction of a new compensating local
fermionic symmetry. In this paper, we extend this "double spinor" formalism to
the case of the supermembrane in 11 dimensions at the classical level. The
basic scheme works in parallel with the string case and we are able to
construct the closed algebra of first class constraints which governs the
entire dynamics of the system. A notable difference from the string case is
that this algebra is first order reducible and the associated BRST operator
must be constructed accordingly. The remaining problems which need to be solved
for the quantization will also be discussed.Comment: 40 pages, no figure, uses wick.sty; v2: a reference added, published
versio
Atividade antioxidante de macrófagos alveolares em ratos endotoxêmicos
Avaliou-se o efeito da endotoxemia sobre a atividade antioxidante de macrófagos alveolares em ratos da linhagem Wistar. Foram utilizados 24 ratos machos, com idade entre 90 e 120 dias, os quais foram divididos em dois grupos: controle e endotoxêmico. O grupo endotoxêmico foi submetido à injeção intraperitonial de lipopolissacarídio na dose de 1mg/kg de peso corporal. Após 24 h, coletou-se sangue para contagem total e diferencial de leucócitos; lavado broncoalveolar para contagem total e diferencial dos leucócitos e, a partir de macrófagos isolados deste lavado, foram realizadas as dosagens de superóxido e superóxido dismutase. A endotoxemia aumentou a contagem total de leucócitos e o número de neutrófilos no sangue periférico, no lavado broncoalveolar, e aumentou a produção de superóxido sem modificar a produção da superóxido dismutase. Esses resultados sugerem que a endotoxemia induz a uma resposta inflamatória no pulmão. Contudo, não altera a atividade antioxidante em ratos adultos. Tal fato potencializa a resposta contra agentes infecciosos pelo hospedeiro, mas também pode contribuir na patogênese de injúria pulmonar.The effects of endotoxemia on the antioxidant activity in alveolar macrophages of Wistar rats were evaluated. Twenty-four male rats, 90-120 days of age, were separated into 2 groups: control and endotoxemic. To the endotoxemic animals was administered, intraperitoneally, a lipopolyssaccaride at dosage of 1mg/kg body weight. Twenty-four hours after this procedure, blood was collected for total and differential leukocytes counts. In addition, bronchoalveolar lavage was collected for total and differential leukocyte counting. From this lavage macrophages were isolated for the dosage of superoxide and superoxide dismutase. The endotoxemia increased the total leukocyte counts and the number of neutrophils in the peripheral blood and bronchoalveolar lavage of the rats. There was an increased superoxide production without changing the superoxide dismutase. Our findings indicate that endotoxemia induces lung inflammatory response. However, it does not alter the antioxidant activity in adult rats. This fact not only enhances host response against infectious agents, but might also contribute to the pathogenesis of pulmonary injury
