Anomaly Cancelations in Orientifolds with Quantized B Flux

TL;DR

This paper investigates anomaly cancellation in Type IIB orientifolds with quantized B-flux, revealing a multiplicity of states and modifications needed for consistency in the open-closed string channel relations.

Contribution

It identifies the role of B-flux in anomaly cancellation and details the required state multiplicities and model modifications for consistency.

Findings

Multiplicity of 59-sector states is 2^{b/2} for even N and B-flux rank b.

Twisted sector R-R scalars and tensors are involved in the Green-Schwarz mechanism.

Modifications to open-closed string channel relations are necessary for model consistency.

Abstract

We consider anomaly cancelations in Type IIB orientifolds on T^4/Z_N with quantized NS-NS sector background B-flux. For a rank b B-flux on T^4 (b is always even) and when N is even, the cancelation requires a 2^{b/2} multiplicity of states in the 59-open string sector. We identify the twisted sector R-R scalars and tensor multiplets which are involved in the Green-Schwarz mechanism. We give more details of the construction of these models and argue that consistency with the 2^{b/2} multiplicity of 59-sector states requires a modification of the relation between the open string 1-loop channel modulus and the closed string tree channel modulus in the 59-cylinder amplitudes.