On the systematics of open-string theories

Self Cite

102

We show that massless RR tadpoles in vacuum configurations with open and unoriented strings are always related to anomalies. RR tadpoles arising from sectors of the internal SCFT with non-vanishing Witten index are in one-to-one correspondence with conventional irreducible anomalies. The anomalous content of the remaining RR tadpoles can be disclosed by considering anomalous amplitudes with higher numbers of external legs. We then provide an explicit parametrization of the anomaly polynomial in terms of the boundary reflection coefficients, i.e. one-point functions of massless RR fields on the disk. After factorization of the reducible anomaly, we extract the relevant WZ couplings in the effective lagrangians.

Section: Introductionmentioning

confidence: 87%

Anomalies and tadpoles

Bianchi

Morales

2000

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102

“…Exploiting the series expansions in q = e −2π collected in an appendix, one finds 11) and extracting the imaginary part by means of…”

Section: Imaginary Part and Total Cross Sectionmentioning

confidence: 99%

String predictions for near future colliders from one-loop scattering amplitudes around D-brane worlds

Bianchi¹,

Santini²

2006

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We derive compact expressions for one-loop scattering amplitudes of four open-string vector bosons around supersymmetric configurations with intersecting or magnetized D-branes on toroidal orbifolds. We check the validity of our formulae against the structure of their singularities and their behaviour under modular transformations to the transverse channel, exposing closed string exchange. We then specialize to the case of forward scattering and compute the total cross section for two massless open string vector bosons on the brane to decay into closed strings in the bulk, relying on the optical theorem. Although not directly related to collider signatures our predictions represent a step forward towards unveiling phenomenological implications of open and unoriented superstrings.1 Unless otherwise stated, we set α ′ = 1/2 henceforth.

“…All the remaining moduli, either charged or neutral, belong to hypemultiplets. In type I constructions [12] various neutral tensor multiplets are present whose scalar components belong to the NS-NS sector.…”

Section: Models In D =mentioning

confidence: 99%

On gauge couplings and thresholds in Type I Gepner models and otherwise

Anastasopoulos¹,

Bianchi²,

Sarkissian³

et al. 2007

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We derive general formulae for tree level gauge couplings and their oneloop thresholds in Type I models based on genuinely interacting internal N = 2 SCFT's, such as Gepner models. We illustrate our procedure in the simple yet non-trivial instance of the Quintic. We briefly address the phenomenologically more relevant issue of determining the Weinberg angle in this class of models. Finally we initiate the study of the correspondence between 'magnetized' or 'coisotropic' D-branes in Gepner models and twisted representations of the underlying N = 2 SCA.