Generation flow in field theory and strings

TL;DR

This paper explores how strong dynamics in field theory and string models can alter the effective number of chiral generations through a process called generation flow, impacting the search for realistic string compactifications.

Contribution

It provides explicit constructions of string models demonstrating generation flow, highlighting the need for careful analysis in string model searches.

Findings

Explicit string models with generation flow constructed

Generation flow can change the number of chiral generations

Traditional string searches may overlook models with generation flow

Abstract

Nontrivial strong dynamics often leads to the appearance of chiral composites. In phenomenological applications, these can either play the role of Standard Model particles or lift chiral exotics by partnering with them in mass terms. As a consequence, the RG flow may change the effective number of chiral generations, a phenomenon we call generation flow. We provide explicit constructions of globally consistent string models exhibiting generation flow. Since such constructions were misclassified in the traditional model searches, our results imply that more care than usually appreciated has to be taken when scanning string compactifications for realistic models.