Orientifolds of Non-Supersymmetric Asymmetric Orbifolds

TL;DR

This paper explores new string vacua derived from asymmetric orbifolds with vanishing cosmological constant, analyzing their supersymmetry properties and brane configurations.

Contribution

It introduces novel non-supersymmetric asymmetric orbifold models with vanishing cosmological constant and examines their brane structures and supersymmetry features.

Findings

Vanishing cosmological constant at one and two loops.

Different supersymmetry levels in bulk and branes.

Identification of Dp and D(p-4) branes or anti-branes.

Abstract

We consider certain four dimensional supersymmetric and non-supersymmetric asymmetric orbifolds with vanishing cosmological constant up to two loops and gauge the world sheet parity transformation. This leads to new string vacua, in which Dp and D(p-4) branes or Dp and anti-D(p-4) are identified. Moreover, it is shown that different degrees of supersymmetry can be realized in the bulk and on the brane. We show that for non-supersymmetric models the cosmological constant still vanishes at one loop order.