TeV-scale Supersymmetric Standard Model and Brane World

TL;DR

This paper introduces a TeV-scale Supersymmetric Standard Model with new states and gauge symmetries that address unification, proton stability, neutrino masses, and quark mass hierarchy, with testable collider predictions.

Contribution

It proposes a novel TeV-scale SUSY model with anomaly-free discrete symmetries, explaining fermion mass hierarchies and proton stability, and discusses distinctive collider signatures.

Findings

Gauge coupling unification at TeV scale similar to MSSM.

Introduction of new states enables anomaly-free discrete symmetries.

Distinct collider signatures for high vs. low unification scale scenarios.

Abstract

Recently we proposed a TeV-scale Supersymmetric Standard Model in which the gauge coupling unification is as precise (at one loop) as in the MSSM, and occurs in the TeV range. One of the key ingredients of this model is the presence of new states neutral under $SU(3)_c\otimes SU(2)_w$ but charged under $U(1)_Y$ whose mass scale is around that of the electroweak Higgs doublets. In this paper we show that introduction of these states allows to gauge novel anomaly free discrete (as well as continuous) symmetries (similar to ``lepton'' and ``baryon'' numbers) which suppress dangerous higher dimensional operators and stabilize proton. Moreover, we argue that these gauge symmetries are essential for successfully generating small neutrino masses via a recently proposed higher dimensional mechanism. Furthermore, the mass hierarchy between the up and down quarks (e.g., $t$ vs. $b$) can be explained without appealing to large $\tan\beta$, and the $\mu$-term for the electroweak Higgs doublets (as well as for the new states) can be generated. We also discuss various phenomenological implications of our model which lead to predictions testable in the present or near future collider experiments. In particular, we point out that signatures of scenarios with high vs. low unification (string) scale might be rather different. This suggest a possibility that the collider experiments may distinguish between these scenarios even without a direct production of heavy Kaluza-Klein or string states.