scholarly journals Quasirealistic heterotic-string models with vanishing one-loop cosmological constant and perturbatively broken supersymmetry?

2008 ◽  
Vol 78 (4) ◽  
Author(s):  
Gerald B. Cleaver ◽  
Alon E. Faraggi ◽  
Elisa Manno ◽  
Cristina Timirgaziu
Keyword(s):  
Cosmological Constant ◽  
Heterotic String ◽  
String Models

scholarly journals de Sitter in non-supersymmetric string theories: no-go theorems and brane-worlds

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Ivano Basile ◽  
Stefano Lanza
Keyword(s):  
Flux Compactifications ◽  
Cosmological Constant ◽  
Dimensional Reduction ◽  
Brane World ◽  
De Sitter ◽  
Top Down ◽  
Brane Worlds ◽  
Concrete Realization ◽  
String Models ◽  
String Theories

Abstract We study de Sitter configurations in ten-dimensional string models where supersymmetry is either absent or broken at the string scale. To this end, we derive expressions for the cosmological constant in general warped flux compactifications with localized sources, which yield no-go theorems that extend previous works on supersymmetric cases. We frame our results within a dimensional reduction and connect them to a number of Swampland conjectures, corroborating them further in the absence of supersymmetry. Furthermore, we construct a top-down string embedding of de Sitter brane-world cosmologies within unstable anti-de Sitter landscapes, providing a concrete realization of a recently revisited proposal.

scholarly journals Classification ofSU(4)×SU(2)×U(1)heterotic-string models

2015 ◽  
Vol 91 (6) ◽  
Author(s):  
Alon E. Faraggi ◽  
Hasan Sonmez
Keyword(s):  
Heterotic String ◽  
String Models

scholarly journals KÄHLER STABILIZED, MODULAR INVARIANT HETEROTIC STRING MODELS

2007 ◽  
Vol 22 (08n09) ◽  
pp. 1451-1588 ◽  
Author(s):  
MARY K. GAILLARD ◽  
BRENT D. NELSON
Keyword(s):  
Heterotic String ◽  
Target Space ◽  
Modular Invariant ◽  
Heterotic String Theory ◽  
Effective Lagrangian ◽  
Parity Conservation ◽  
Weakly Coupled ◽  
String Models ◽  
Early Universe Cosmology

We review the theory and phenomenology of effective supergravity theories based on orbifold compactifications of the weakly-coupled heterotic string. In particular, we consider theories in which the four-dimensional theory displays target space modular invariance and where the dilatonic mode undergoes Kähler stabilization. A self-contained exposition of effective Lagrangian approaches to gaugino condensation and heterotic string theory is presented, leading to the development of the models of Binétruy, Gaillard and Wu. Various aspects of the phenomenology of this class of models are considered. These include issues of supersymmetry breaking and superpartner spectra, the role of anomalous U(1) factors, issues of flavor and R-parity conservation, collider signatures, axion physics, and early universe cosmology. For the vast majority of phenomenological considerations the theories reviewed here compare quite favorably to other string-derived models in the literature. Theoretical objections to the framework and directions for further research are identified and discussed.

scholarly journals NON-ABELIAN FLAT DIRECTIONS IN A MINIMAL SUPERSTRING STANDARD MODEL

2000 ◽  
Vol 15 (18) ◽  
pp. 1191-1202 ◽  
Author(s):  
G. B. CLEAVER ◽  
D. V. NANOPOULOS ◽  
J. W. WALKER ◽  
A. E. FARAGGI
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Effective Field Theory ◽  
Effective Field ◽  
Heterotic String ◽  
Charged Matter ◽  
Hidden Sector ◽  
Abelian Fields ◽  
String Models

Recently, by studying exact flat directions of non-Abelian singlet fields, we demonstrated the existence of free fermionic heterotic-string models in which the SU (3)C× SU (2)L×U(1)Y-charged matter spectrum reduces to that of the MSSM in the effective field theory. In this letter we generalize the analysis to include vevs of non-Abelian fields. We find MSSM-producing, exact non-Abelian flat directions, which are the first such examples in the literature. We examine the possibility that hidden sector condensates lift the flat directions.

Connection between spectra of non-supersymmetric heterotic string models

1987 ◽  
Vol 189 (1-2) ◽  
pp. 52-56 ◽  
Author(s):  
S. Elitzur ◽  
A. Giveon
Keyword(s):  
Heterotic String ◽  
String Models

FOUR-DIMENSIONAL HETEROTIC STRING MODELS WITH SU(3) × SU(2) × Up(1) LOW ENERGY GAUGE GROUP

1989 ◽  
Vol 04 (17) ◽  
pp. 4475-4485 ◽  
Author(s):  
DAVID BAILIN ◽  
ALEX LOVE
Keyword(s):  
Gauge Group ◽  
Degrees Of Freedom ◽  
Low Energy ◽  
Heterotic String ◽  
String Models

A study is made of a class of four-dimensional heterotic string models with complex fermionic degrees of freedom to discover whether there are any examples with 3 or 4 generations of quarks and leptons and SU C(3) × SU L(2) × U p(1) low energy gauge group.

Two-loop vacuum amplitude in four-dimensional heterotic string models

1988 ◽  
Vol 211 (4) ◽  
pp. 425-430 ◽  
Author(s):  
Roberto Iengo ◽  
Galen M. Sotkov ◽  
Chuan-Jie Zhu
Keyword(s):  
Heterotic String ◽  
String Models
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