U(1)' solution to the mu-problem and the proton decay problem in supersymmetry without R-parity

TL;DR

This paper proposes a U(1)'-extended MSSM model that simultaneously addresses the mu-problem and proton decay issues without R-parity, ensuring proton stability and offering new collider phenomenology opportunities.

Contribution

It introduces a novel U(1)' symmetry framework that forbids dangerous proton decay operators and solves key supersymmetric problems without R-parity.

Findings

Models automatically forbid lepton and baryon number violation coexistence.

Proton decay operators are suppressed by the U(1)' symmetry.

The framework remains viable with minimal exotic fields for anomaly cancellation.

Abstract

The Minimal Supersymmetric Standard Model (MSSM) is plagued by two major fine-tuning problems: the mu-problem and the proton decay problem. We present a simultaneous solution to both problems within the framework of a U(1)'-extended MSSM (UMSSM), without requiring R-parity conservation. We identify several classes of phenomenologically viable models and provide specific examples of U(1)' charge assignments. Our models generically contain either lepton number violating or baryon number violating renormalizable interactions, whose coexistence is nevertheless automatically forbidden by the new U(1)' gauge symmetry. The U(1)' symmetry also prohibits the potentially dangerous and often ignored higher-dimensional proton decay operators such as QQQL and UUDE which are still allowed by R-parity. Thus, under minimal assumptions, we show that once the mu-problem is solved, the proton is sufficiently stable, even in the presence of a minimum set of exotics fields, as required for anomaly cancellation. Our models provide impetus for pursuing the collider phenomenology of R-parity violation within the UMSSM framework.