Asymmetric Gepner models (revisited)

Abstract

We reconsider a class of heterotic string theories studied in 1989, based on tensor products of N = 2 minimal models with asymmetric simple current invariants. We extend this analysis from (2, 2) and (1, 2) spectra to (0, 2) spectra with SO(10) broken to the Standard Model. In the latter case the spectrum must contain fractionally charged particles. We find that in nearly all cases at least some of them are massless. However, we identify a large subclass where the fractional charges are at worst half-integer, and often vector-like. The number of families is very often reduced in comparison to the 1989 results, but there are no new tensor combinations yielding three families. All tensor combinations turn out to fall into two classes: those where the number of families is always divisible by three, and those where it is never divisible by three. We find an empirical rule to determine the class, which appears to extend beyond minimal N = 2 tensor products. We observe that distributions of physical quantities such as the number of families, singlets and mirrors have an interesting tendency towards smaller values as the gauge groups approaches the Standard Model. We compare our results with an analogous class of free fermionic models. This displays similar features, but with less resolution. Finally we present a complete scan of the three family models based on the triply-exceptional combination (1, 16 * , 16 * , 16 * ) identified originally by Gepner. We find 1220 distinct three family spectra in this case, forming 610 mirror pairs. About half of them have the gauge group SU (3) × SU (2) L × SU (2) R × U (1) 5 , the theoretical minimum, and many others are trinification models.

FlippedSU(5)string vacua classification: A variation of theSO(10)breaking basis ve

“…[1] and in this paper show that no three-chiral-generation models exist and that they only exist with the inclusion of four exotic multiplets as given in the model above. Although this was a surprising feature, it is however in line with related searches [51].…”

Life at the interface of particle physics and string theory

“…These authors did find examples with three families where all fractionally charged particles are at the Planck mass, but only in a fraction of 10 −5 of the chiral spectra. In Gato-Rivera and Schellekens (2010Schellekens ( , 2011a; and Maio and Schellekens (2011) a similar small fraction was seen, but examples were found only for even numbers of families. These authors also compared the total number of spectra with chiral and vector-like fractional charges, and found that in about 5% to 20% of the chiral, non-GUT spectra the fractional charges are massless, but vector-like.…”

The asymmetric CFT landscape in with extended supersymmetry

“…it is not clear which minima of GSUGRA belong to the string landscape and which to the swampland. This work can be considered as the continuation of a series of papers that started with the construction of Gepner models [20][21][22][23], their extension by the simple current technique [24,25] for constructing ACFTs [26][27][28][29][30], and the recent attempt [16] to relate some of these four-dimensional ACFTs to minima of N = 2 GSUGRA partially-broken to N = 1.…”