scholarly journals Low fine-tuning in Yukawa-deflected gauge mediation

2017 ◽  
Vol 95 (9) ◽  
Author(s):  
Waqas Ahmed ◽  
Lorenzo Calibbi ◽  
Tianjun Li ◽  
Azar Mustafayev ◽  
Shabbar Raza
Keyword(s):  
Fine Tuning ◽  
Gauge Mediation

WHY IS THE HIDDEN SECTOR INVISIBLE?

2000 ◽  
Vol 15 (35) ◽  
pp. 2131-2137 ◽  
Author(s):  
M. D. POLLOCK
Keyword(s):  
Degrees Of Freedom ◽  
Coupling Parameter ◽  
Vacuum State ◽  
Fine Tuning ◽  
Gauge Mediation ◽  
Superstring Theory ◽  
Thermodynamical Equilibrium ◽  
Hidden Sector ◽  
Axion Field ◽  
Model Independent

The hidden sector of the E8×E′8 heterotic superstring theory of Gross et al. can in principle contain additional "shadow" matter, interacting only gravitationally with the real world in which we live. The SU (3)′ C × SU (2)′ L × U (1)′ Y shadow configuration symmetric to the standard model has been ruled out by Kolb et al. from nucleosynthesis arguments, combined with the existence of three light neutrinos. In the absence of inflation and of entropy enhancement by the out-of-equilibrium decay of an unstable particle, the same exclusion applies to the unbroken E′8 hidden gauge group, assuming thermodynamical equilibrium with the observable sector E6 group, and consequently all breaking chains E′8→ G1×G2×⋯, since they can only reduce the effective number of four-dimensional degrees of freedom g eff . The hidden sector would then appear to be in its vacuum state, which implies the absence of all condensates as well, if their potentials are positive semi-definite. In this case, and if there is no anomalous U(1) symmetry in the observable sector, the QCD axion is the model-independent axion, whose decay constant [Formula: see text] (where [Formula: see text] is the strong-interaction coupling parameter) requires a fine-tuning of the initial value of this axion field to ai/fa≲3×10-3, in order not to overclose the Universe today, supersymmetry being broken by gauge mediation. Vice versa, if ai/fa~1, then hidden-sector gaugino condensation is necessary for there to be a sufficiently massive gravitino, whose decay can increase the entropy. Astronomical microlensing observations may help to discriminate between these two cases.

scholarly journals Focus point gauge mediation without a severe fine-tuning

2018 ◽  
Vol 2018 (10) ◽  
Author(s):  
Tsutomu T. Yanagida ◽  
Norimi Yokozaki
Keyword(s):  
Fine Tuning ◽  
Gauge Mediation ◽  
Focus Point

scholarly journals Fine tuning in general gauge mediation

2010 ◽  
Vol 2010 (1) ◽  
Author(s):  
Tatsuo Kobayashi ◽  
Yuichiro Nakai ◽  
Ryo Takahashi
Keyword(s):  
Fine Tuning ◽  
Gauge Mediation ◽  
General Gauge

scholarly journals Charms of strongly interacting conformal gauge mediation

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Gong jun Choi ◽  
Tsutomu T. Yanagida ◽  
Norimi Yokozaki
Keyword(s):  
Production Cross ◽  
Mass Scale ◽  
Susy Breaking ◽  
Fine Tuning ◽  
Gauge Mediation ◽  
Gravitino Mass ◽  
Strongly Interacting ◽  
Conformal Gauge ◽  
Single Mass ◽  
Breaking Scale

Abstract By extending a previously proposed conformal gauge mediation model, we construct a gauge-mediated SUSY breaking (GMSB) model where a SUSY-breaking scale, a messenger mass, the μ-parameter and the gravitino mass in a minimal supersymmetric (SUSY) Standard Model (MSSM) are all explained by a single mass scale, a R-symmetry breaking scale. We focus on a low scale SUSY-breaking scenario with the gravitino mass m3/2 = $$ \mathcal{O}(1)\mathrm{eV} $$ O 1 eV , which is free from the cosmological gravitino problem and relaxes the fine-tuning of the cosmological constant. Both the messenger and SUSY-breaking sectors are subject to a hidden strong dynamics with the conformality above the messenger mass threshold (and hence the name of the model “strongly interacting conformal gauge mediation”). In our model, the Higgs B-term is suppressed and a large tan β is predicted, resulting in the relatively light second CP-even Higgs and the CP-odd Higgs with a sizable production cross section. These Higgs bosons can be tested at future LHC experiments.

scholarly journals Bounds on scalar masses in theories of moduli stabilization

2014 ◽  
Vol 29 (11n12) ◽  
pp. 1450073 ◽  
Author(s):  
Bobby Samir Acharya ◽  
Gordon Kane ◽  
Eric Kuflik
Keyword(s):  
Dark Matter ◽  
String Theory ◽  
Direct Detection ◽  
Fine Tuning ◽  
Gauge Mediation ◽  
Moduli Stabilization ◽  
Gravitino Mass ◽  
Matter Production ◽  
History Of ◽  
The Universe

In recent years it has been realized that pre-BBN decays of moduli can be a significant source of dark matter production, giving a "nonthermal WIMP miracle" and substantially reduced fine-tuning in cosmological axion physics. We study moduli masses and sharpen the claim that moduli dominated the pre-BBN universe. We conjecture that in any string theory with stabilized moduli there will be at least one modulus field whose mass is of order (or less than) the gravitino mass. Cosmology then generically requires the gravitino mass not be less than about 30 TeV and the cosmological history of the universe is nonthermal prior to BBN. Stable LSP's produced in these decays can account for the observed dark matter if they are "wino-like." We briefly consider implications for the LHC, rare decays, and dark matter direct detection and point out that these results could prove challenging for models attempting to realize gauge mediation in string theory.

Fine-Tuning Futures

ASHA Leader ◽  
2017 ◽  
Vol 22 (6) ◽  
Author(s):  
Christi Miller
Keyword(s):  
Fine Tuning

Food Safety Security: A new Concept for Enhancing Food Safety Measures

2012 ◽  
Vol 82 (3) ◽  
pp. 216-222 ◽  
Author(s):  
Venkatesh Iyengar ◽  
Ibrahim Elmadfa
Keyword(s):  
Food Safety ◽  
Hazard Analysis ◽  
Warning System ◽  
Shared Responsibility ◽  
Fine Tuning ◽  
Strategic Action ◽  
Surveillance Network ◽  
Measurement Systems ◽  
Critical Control Points ◽  
The Impact

The food safety security (FSS) concept is perceived as an early warning system for minimizing food safety (FS) breaches, and it functions in conjunction with existing FS measures. Essentially, the function of FS and FSS measures can be visualized in two parts: (i) the FS preventive measures as actions taken at the stem level, and (ii) the FSS interventions as actions taken at the root level, to enhance the impact of the implemented safety steps. In practice, along with FS, FSS also draws its support from (i) legislative directives and regulatory measures for enforcing verifiable, timely, and effective compliance; (ii) measurement systems in place for sustained quality assurance; and (iii) shared responsibility to ensure cohesion among all the stakeholders namely, policy makers, regulators, food producers, processors and distributors, and consumers. However, the functional framework of FSS differs from that of FS by way of: (i) retooling the vulnerable segments of the preventive features of existing FS measures; (ii) fine-tuning response systems to efficiently preempt the FS breaches; (iii) building a long-term nutrient and toxicant surveillance network based on validated measurement systems functioning in real time; (iv) focusing on crisp, clear, and correct communication that resonates among all the stakeholders; and (v) developing inter-disciplinary human resources to meet ever-increasing FS challenges. Important determinants of FSS include: (i) strengthening international dialogue for refining regulatory reforms and addressing emerging risks; (ii) developing innovative and strategic action points for intervention {in addition to Hazard Analysis and Critical Control Points (HACCP) procedures]; and (iii) introducing additional science-based tools such as metrology-based measurement systems.

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