2025/03/31 by Funakoshi, Shuta, Koga, Yuichi, Otsuka, Hajime · 2 citations
#FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High Energy Physics - Theory (hep-th)
paper · doi:10.48550/arxiv.2503.23741
We study modular symmetries in non-supersymmetric heterotic string theories on toroidal backgrounds with Wilson line modulus, constructed by stringy Scherk-Schwartz compactification. In particular, we focus on a subgroup of the T-duality group O(D+16,D,ℤ) with D=2 given by an outer automorphism of the Narain lattice, which can be mapped to the Siegel modular group Sp(4,ℤ). We classify the modular symmetries and a CP-like symmetry on T2 and its orbifolds with symmetric and asymmetric orbifold twists. It turns out that the non-supersymmetric heterotic string theories only enjoy a part of modular symmetries in contrast to supersymmetric ones. Furthermore, the gauge symmetry is maximally enhanced at fixed points of modular symmetries on T2 on which we analyze the vacuum structure of eight-dimensional tachyon-free vacua.