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A Chiral Supersymmetric Standard Model

Hsin-Chia Cheng, Bogdan A. Dobrescu, Konstantin T. Matchev

TL;DR

This work presents a purely chiral extension of the Standard Model with an anomaly-free $U(1)_μ$ that forbids all supersymmetric mass terms, including the $μ$-term, and communicates SUSY breaking via gauge mediation. A dynamical SUSY-breaking (DSB) sector together with anomaly-canceling messenger fields generates a realistic $μ$ through $U(1)_μ$ breaking and yields a gaugino- and scalar-mass spectrum governed by a low-scale mediation, with a characteristic $Λ ≈ 2√3 (λ/ε) \tilde m$ and $ε \ll λ$. The model predicts a SUSY-breaking scale potentially as low as $E_{vac} \sim 10^6$ GeV, enabling NLSP decays inside detectors and yielding distinctive collider phenomenology, while preserving $R$-parity and offering a coherent mechanism for anomaly cancellation and MSSM coupling to the DSB sector. This constitutes the first explicit example of a purely chiral SUSY Standard Model with calculable dynamics and testable predictions at colliders.

Abstract

We propose a supersymmetric extension of the Standard Model with an extra U(1) gauge symmetry, so that all supersymmetric mass terms, including the $μ$-term, are forbidden by the gauge symmetries. Supersymmetry is broken dynamically which results in U(1) breaking and generation of realistic $μ$ term and soft breaking masses. The additional fields required to cancel the U(1) anomalies are identified with the messengers of supersymmetry breaking. The gaugino masses arise as in the usual gauge mediated scenario, while squarks and sleptons receive their masses from both the U(1) $D$-term and the two-loop gauge mediation contributions. The scale of supersymmetry breaking in this model can be below $10^6$ GeV, yielding collider signatures with decays to goldstinos inside the detector.

A Chiral Supersymmetric Standard Model

TL;DR

This work presents a purely chiral extension of the Standard Model with an anomaly-free that forbids all supersymmetric mass terms, including the -term, and communicates SUSY breaking via gauge mediation. A dynamical SUSY-breaking (DSB) sector together with anomaly-canceling messenger fields generates a realistic through breaking and yields a gaugino- and scalar-mass spectrum governed by a low-scale mediation, with a characteristic and . The model predicts a SUSY-breaking scale potentially as low as GeV, enabling NLSP decays inside detectors and yielding distinctive collider phenomenology, while preserving -parity and offering a coherent mechanism for anomaly cancellation and MSSM coupling to the DSB sector. This constitutes the first explicit example of a purely chiral SUSY Standard Model with calculable dynamics and testable predictions at colliders.

Abstract

We propose a supersymmetric extension of the Standard Model with an extra U(1) gauge symmetry, so that all supersymmetric mass terms, including the -term, are forbidden by the gauge symmetries. Supersymmetry is broken dynamically which results in U(1) breaking and generation of realistic term and soft breaking masses. The additional fields required to cancel the U(1) anomalies are identified with the messengers of supersymmetry breaking. The gaugino masses arise as in the usual gauge mediated scenario, while squarks and sleptons receive their masses from both the U(1) -term and the two-loop gauge mediation contributions. The scale of supersymmetry breaking in this model can be below GeV, yielding collider signatures with decays to goldstinos inside the detector.

Paper Structure

This paper contains 5 sections, 23 equations, 1 figure, 2 tables.

Table of Contents

  1. Introduction
  2. Model Building
  3. Sparticle spectrum
  4. Discussion
  5. The DSB Sector

Figures (1)

  • Figure 1: RGE evolution of the soft mass parameters: gaugino masses (dotted lines), first two generation squark masses (dashed) and stop, stau and Higgs masses (solid). Since the soft Higgs masses can be negative, we plot ${\rm sign}(m^2)\sqrt{|m^2|}$.