# Emerging Internal Symmetries from Effective Spacetimes

## TL;DR

This paper explores how internal and spacetime symmetries can be interconnected in effective 4D theories derived from higher-dimensional Minkowski spacetimes without relying on supersymmetry, expanding understanding of symmetry mixing.

## Contribution

It demonstrates conditions under which external symmetries induce internal symmetries in 4D theories from higher-dimensional spacetimes without supersymmetry, providing new mechanisms for symmetry mixing.

## Key findings

- External symmetries can induce internal symmetries in 4D theories.
- Orthogonal extra dimensions can have symmetries that mix with internal symmetries.
- Mechanisms for symmetry mixing without supersymmetry are identified.

## Abstract

Can global internal and spacetime symmetries be connected without supersymmetry? To answer this question, we investigate Minkowski spacetimes with d space-like extra dimensions and point out under which general conditions external symmetries induce internal symmetries in the effective 4-dimensional theories. We further discuss in this context how internal degrees of freedom and spacetime symmetries can mix without supersymmetry in agreement with the Coleman-Mandula theorem. We present some specific examples which rely on a direct product structure of spacetime such that orthogonal extra dimensions can have symmetries which mix with global internal symmetries. This mechanism opens up new opportunities to understand global symmetries in particle physics.