FLIPPED SU(6) FROM TEN DIMENSIONS

1990 ◽  
Vol 05 (12) ◽  
pp. 2359-2390 ◽  
Author(s):  
C. PANAGIOTAKOPOULOS
Keyword(s):  
Discrete Symmetries ◽  
Model Building ◽  
Realistic Model ◽  
Low Energy ◽  
Internal Space ◽  
Fast Proton ◽  
Hierarchy Problem ◽  
Four Dimensions ◽  
Gauge Hierarchy ◽  
Breaking Scale

We study the compactification of the heterotic superstring on the only known three generation Calabi-Yau space with flux breakings leading to SU (6) × U (1) as the gauge group in four dimensions. We compute the 'massless' spectrum and identify the discrete symmetries of the internal space that survive flux breaking. The possible four-dimensional models are classified according to their honest discrete symmetries. The allowed breaking chains of SU (6) × U (1) are listed. Model building with SU (6) × U (1) is discussed in general and a concrete realistic model is constructed which does not suffer from the gauge hierarchy problem, fast proton decay or any other obvious phenomenological disaster. A distinct experimental signature of this class of models is the presence in the low energy spectrum of vector-like quarks and antiquarks, outside the three known families, with masses of the order of the supersymmetry breaking scale.

scholarly journals Discrete Symmetries of Complete Intersection Calabi–Yau Manifolds

2020 ◽  
Vol 379 (3) ◽  
pp. 847-865
Author(s):  
Andre Lukas ◽  
Challenger Mishra
Keyword(s):  
String Theory ◽  
Complete Intersection ◽  
Discrete Symmetries ◽  
Model Building ◽  
Low Energy ◽  
Discrete Groups ◽  
Dimensional Model ◽  
Group Order ◽  
String Compactifications ◽  
Calabi Yau Manifolds

Abstract In this paper, we classify non-freely acting discrete symmetries of complete intersection Calabi–Yau manifolds and their quotients by freely-acting symmetries. These non-freely acting symmetries can appear as symmetries of low-energy theories resulting from string compactifications on these Calabi–Yau manifolds, particularly in the context of the heterotic string. Hence, our results are relevant for four-dimensional model building with discrete symmetries and they give an indication which symmetries of this kind can be expected from string theory. For the 1695 known quotients of complete intersection manifolds by freely-acting discrete symmetries, non-freely-acting, generic symmetries arise in 381 cases and are, therefore, a relatively common feature of these manifolds. We find that 9 different discrete groups appear, ranging in group order from 2 to 18, and that both regular symmetries and R-symmetries are possible.

scholarly journals GAUGE SYMMETRY BREAKING IN ORBIFOLD MODEL BUILDING

2006 ◽  
Vol 21 (30) ◽  
pp. 2251-2267 ◽  
Author(s):  
MICHELE TRAPLETTI
Keyword(s):  
Gauge Symmetry ◽  
Symmetry Breaking ◽  
Extra Dimensions ◽  
Model Building ◽  
String Model ◽  
Open String ◽  
Internal Space ◽  
Four Dimensions ◽  
String Compactifications ◽  
Breaking Mechanism

We review the gauge symmetry breaking mechanism due to orbifold projections in orbifold model building. We explicitly show the existence of a scale of breaking if such a symmetry breaking is due to freely-acting orbifold operators only, i.e. in case the breaking is realized nonlocally in the internal space. We show that such a scale is related to the compactification moduli only, and that there are no extra continuous parameters, at least in semirealistic models with [Formula: see text] SUSY in four dimensions. In this sense, the mechanism is peculiarly different from the standard Higgs (or Hosotani) symmetry breaking mechanism. We show that the mechanism also differs from that present in standard orbifold models where, even in the presence of discrete Wilson lines, a scale of breaking is generically missing, since the breaking is localized in specific points in the internal space. We review a set of background geometries where the described nonlocal breaking is realized, both in the case of two and six extra dimensions. In the latter case, relevant in string model building, we consider both heterotic and open string compactifications.

scholarly journals Pure geometric branes and mass hierarchy

2014 ◽  
Vol 29 (23) ◽  
pp. 1450120 ◽  
Author(s):  
Ke Yang ◽  
Yuan Zhong ◽  
Shao-Wen Wei ◽  
Yu-Xiao Liu
Keyword(s):  
Mass Spectrum ◽  
Low Energy ◽  
Mass Hierarchy ◽  
Graviton Mass ◽  
Hierarchy Problem ◽  
Weakly Coupled ◽  
Gauge Hierarchy ◽  
Weyl Scalar

We consider a toy model with flat thin branes embedded in a five-dimensional Weyl integrable manifold, where the geometric Weyl scalar provides the material that constitute the brane configurations. The brane configuration is similar to the Randall–Sundrum model. However, it is found that the massless graviton is localized on the brane with negative tension. So, in order to solve the gauge hierarchy problem, our world should be confined on the positive tension brane, and this is crucial to reproduce a correct Friedmann-like equation on the brane. The spacings of graviton mass spectrum are very tiny, but these massive gravitons are hidden in low energy experiments because they are weakly coupled with matter on the brane.

scholarly journals Marlim R3D: a realistic model for CSEM simulations - phase I: model building

2017 ◽  
Vol 47 (4) ◽  
pp. 633-644 ◽  
Author(s):  
Bruno Rodrigues Carvalho ◽  
Paulo Tarso Luiz Menezes
Keyword(s):  
Model Building ◽  
Reference Model ◽  
Sedimentary Basins ◽  
Realistic Model ◽  
Complex Model ◽  
Well Log ◽  
Recent Past ◽  
Complementary Information ◽  
Geoelectric Model ◽  
Calibration Time

ABSTRACT: The marine controlled-source electromagnetic (CSEM) method provides complementary information to seismic imaging in the exploration of sedimentary basins. The CSEM is mainly used for reservoir scanning and appraisal. The CSEM interpretation workflow is heavily based on inversion and forward - modeling for hypothesis testing. Until the recent past, the effectiveness of a given workflow was achieved after the drilling results, as there wasn’t any geological complex model available to serve as a benchmark. In the present paper, we describe the workflow to build up Marlim R3D, a realistic and complex geoelectric model. Marlim R3D aims to be a reference model of turbidite reservoirs of the Brazilian continental margin. Our model is based on seismic interpretation and constrained by the input of available well-log information. The workflow used is composed of seven steps: seismic and well-log dataset loading, well-tie, Vp cube construction, Vp resistivity calibration, time-depth conversion, resistivity cube construction, and quality-control check. As a result, we obtained an interpreted dataset composed by main stratigraphic horizons, pseudo-well logs, and the resistivity cubes. These elements were made freely available for research or commercial use, under the Creative Common License, at the Zenodo platform.

scholarly journals A FOUR-DIMENSIONAL SUPERSTRING FROM THE BOSONIC STRING WITH SOME APPLICATIONS

2005 ◽  
Vol 20 (01) ◽  
pp. 99-128 ◽  
Author(s):  
B. B. DEO ◽  
L. MAHARANA
Keyword(s):  
Standard Model ◽  
Central Charge ◽  
Virasoro Algebra ◽  
Low Energy ◽  
Majorana Fermions ◽  
Modular Invariance ◽  
Model Group ◽  
Supersymmetry Algebra ◽  
Four Dimensions ◽  
Bosonic Representation

A string in four dimensions is constructed by supplementing it with 44 Majorana fermions. The later are represented by 11 vectors in the bosonic representation SO (D-1,1). The central charge is 26. The fermions are grouped in such a way that the resulting action is worldsheet supersymmetric. The energy–momentum and current generators satisfy the super-Virasoro algebra. GSO projections are necessary for proving modular invariance. Space–time supersymmetry algebra is deduced and is substantiated for specific modes of zero mass. The symmetry group of the model can descend to the low energy standard model group SU (3)× SU L(2)× U Y(1) through the Pati–Salam group.

scholarly journals MEDIATION OF SUPERSYMMETRY BREAKING IN EXTRA DIMENSIONS

2005 ◽  
Vol 20 (05) ◽  
pp. 297-312 ◽  
Author(s):  
CLAUDIO A. SCRUCCA
Keyword(s):  
Supersymmetry Breaking ◽  
Effective Field Theory ◽  
Extra Dimensions ◽  
Model Building ◽  
Realistic Model ◽  
Effective Field ◽  
Theory Approach ◽  
Classical Level ◽  
Gravitational Effects ◽  
Gravitational Fields

We review the mechanisms of supersymmetry breaking mediation that occur in sequestered models, where the visible and the hidden sectors are separated by an extra dimension and communicate only via gravitational interactions. By locality, soft breaking terms are forbidden at the classical level and reliably computable within an effective field theory approach at the quantum level. We present a self-contained discussion of these radiative gravitational effects and the resulting pattern of soft masses, and give an overview of realistic model building based on this setup. We consider both flat and warped extra dimensions, as well as the possibility that there be localized kinetic terms for the gravitational fields.

CLASSICAL INSTABILITY OF THE EINSTEIN-GAUSS-BONNET GRAVITY THEORY WITH COMPACTIFIED HIGHER DIMENSIONS

1991 ◽  
Vol 06 (25) ◽  
pp. 4517-4555 ◽  
Author(s):  
LESZEK M. SOKOŁOWSKI ◽  
ZDZISŁAW A. GOLDA ◽  
MARCO LITTERIO ◽  
LUCA AMENDOLA
Keyword(s):  
Scalar Fields ◽  
Gravity Theory ◽  
Effective Theory ◽  
Internal Space ◽  
Bonnet Gravity ◽  
Four Dimensions ◽  
Effective Gravity ◽  
Tensor Theory ◽  
Exciting System ◽  
Bonnet Term

The energy spectrum and stability of the effective theory resulting from the Einstein-Gauss-Bonnet gravity theory with compactified internal space are investigated. The internal space can evolve in its volume and/or shape, giving rise to a system of scalar fields in the external space-time. The resulting scalar-tensor theory of gravity has physically unacceptable properties. First of all, the scalar fields’ energy is indefinite and unbounded from below, and thereby the gravitational and scalar fields form a self-exciting system. In contradistinction to the case of multidimensional Einstein gravity, this inherent instability of the effective theory cannot be removed by field redefinitions in the process of dimensional reduction (e.g. by a conformal rescaling of the metric in four dimensions, as is done in the former case). To get a viable effective gravity theory one should discard either the geometric scalar fields or the Gauss-Bonnet term from the Lagrangian of the multidimensional theory. It is argued that it is the Gauss-Bonnet term that should be discarded.

Measuring Utilization of ERP Systems Usage in SMEs

2013 ◽  
pp. 22-34
Author(s):  
Hedman Jonas ◽  
Johansson Björn
Keyword(s):  
Enterprise Resource Planning ◽  
Model Building ◽  
Critical Mass ◽  
Resource Planning ◽  
Erp Systems ◽  
Planning Systems ◽  
Four Dimensions ◽  
Factors Influencing ◽  
Enterprise Resource Planning Systems ◽  
The Many

Since deployment of Enterprise Systems (ES) such as Enterprise Resource Planning systems (ERPs) within enterprises, both Large Enterprises (LEs) as well as Small and Medium-sized Enterprises (SMEs) have increased and continue to increase, making it increasingly desirable to measure the degree of utilization of ERP systems in enterprises. One reason for this interest is that no benefits are realized if the systems are not used; since ERPs are massive investments, they need to show benefits, or at least be able to measure the benefits. However, to be able to do so, there is a need to explain ERP systems utilization and the factors that influence ERP utilization. This chapter provides an explanation of factors influencing ERP systems utilization by testing a research model building on four dimensions: volume, breadth, diversity, and depth. The contributions of the research are: First, it provides support for the notion of diffusion found in the theory of network externalities where a critical mass is necessary to achieve benefits. This can be used to better understand failures in ERP projects. Second, the use of volume, breadth and depth provide insights for use as a construct and the need to treat it more rigorously. Third, the study contributes to our understanding of the many aspects of use of IT, such as ERPs, and potentially contributes to value and firm performance from ERP utilization.

scholarly journals INFINITE STATISTICS, SYMMETRY BREAKING AND COMBINATORIAL HIERARCHY

2009 ◽  
Vol 24 (18) ◽  
pp. 1425-1435 ◽  
Author(s):  
VLADIMIR SHEVCHENKO
Keyword(s):  
Symmetry Breaking ◽  
Mechanical Model ◽  
Degrees Of Freedom ◽  
High Energy ◽  
Low Energy ◽  
Effective Theory ◽  
Quantum Mechanical ◽  
Hierarchy Problem ◽  
Induced Gravity ◽  
Large Numbers

The physics of symmetry breaking in theories with strongly interacting quanta obeying infinite (quantum Boltzmann) statistics known as quons is discussed. The picture of Bose/Fermi particles as low energy excitations over nontrivial quon condensate is advocated. Using induced gravity arguments, it is demonstrated that the Planck mass in such low energy effective theory can be factorially (in number of degrees of freedom) larger than its true ultraviolet cutoff. Thus, the assumption that statistics of relevant high energy excitations is neither Bose nor Fermi but infinite can remove the hierarchy problem without necessity to introduce any artificially large numbers. Quantum mechanical model illustrating this scenario is presented.

scholarly journals THE GAUGE HIERARCHY PROBLEM AND HIGHER-DIMENSIONAL GAUGE THEORIES

1998 ◽  
Vol 13 (32) ◽  
pp. 2601-2611 ◽  
Author(s):  
HISAKI HATANAKA ◽  
TAKEO INAMI ◽  
C. S. LIM
Keyword(s):  
Higgs Mass ◽  
Quantum Correction ◽  
Gauge Theories ◽  
Finite Mass ◽  
Hierarchy Problem ◽  
Mass Correction ◽  
Higher Dimensional ◽  
Gauge Hierarchy ◽  
Simply Connected ◽  
Matter Fields

We report on an attempt to solve the gauge hierarchy problem in the framework of higher-dimensional gauge theories. Both classical Higgs mass and quadratically divergent quantum correction to the mass are argued to be vanished. Hence the hierarchy problem in its original sense is solved. The remaining finite mass correction is shown to depend crucially on the choice of boundary condition for matter fields, and a way to fix it dynamically is presented. We also point out that on the simply-connected space S2 even the finite mass correction vanishes.

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