scholarly journals Gauge coupling unification in heterotic string models with gauge mediated supersymmetry breaking

2011 ◽  
Vol 83 (7) ◽  
Author(s):  
Archana Anandakrishnan ◽  
Stuart Raby
Keyword(s):  
Supersymmetry Breaking ◽  
Gauge Coupling ◽  
Heterotic String ◽  
String Models

scholarly journals M-Theory Inspired No-Scale Supergravity

1997 ◽  
Vol 12 (35) ◽  
pp. 2647-2653 ◽  
Author(s):  
Tianjun Li ◽  
D. V. Nanopoulos ◽  
Jorge L. Lopez
Keyword(s):  
Supersymmetry Breaking ◽  
Gauge Coupling ◽  
Heterotic String ◽  
Particle Accelerators ◽  
Intermediate Scale ◽  
Strongly Coupled ◽  
Present Generation ◽  
Kähler Potential ◽  
M Theory

We propose a supergravity model that contains elements recently shown to arise in the strongly-coupled limit of the E8 × E8 heterotic string (M-theory), including a no-scale-like Kähler potential, the identification of the string scale with the gauge coupling unification scale, and the onset of supersymmetry breaking at an intermediate scale determined by the size of the 11th dimension of M-theory. We also study the phenomenological consequences of such scenario, which include a rather constrained sparticle spectrum within the reach of present-generation particle accelerators.

scholarly journals STRING NO-SCALE SUPERGRAVITY

1996 ◽  
Vol 11 (19) ◽  
pp. 3439-3477 ◽  
Author(s):  
JORGE L. LOPEZ ◽  
D.V. NANOPOULOS
Keyword(s):  
Supersymmetry Breaking ◽  
Vacuum Energy ◽  
Scalar Potential ◽  
Gauge Coupling ◽  
Supersymmetric Particle ◽  
Scale Models ◽  
Fermionic String ◽  
Soft Supersymmetry Breaking ◽  
The Stability ◽  
String Models

We explore the postulates of string no-scale supergravity in the context of free-fermionic string models. The requirements of vanishing vacuum energy, flat directions of the scalar potential, and stable no-scale mechanism impose strong restrictions on possible string no-scale models, which must possess only two or three moduli, and a constrained massless spectrum. The soft-supersymmetry-breaking parameters involving all twisted and untwisted fields are given explicitly. Our calculations take into account the possible existence of an anomalous U A(1) factor in the gauge group, and reveal some novel effects concerning the stability of the no-scale mechanism in the presence of U A(1). This class of models contains no free parameters, i.e. in principle all supersymmetric particle masses and interactions are completely determined. A computerized search for free-fermionic models with the desired properties yields a candidate SU (5)×U(1) model containing extra [Formula: see text] matter representations that allow gauge coupling unification at the string scale. Our candidate model possesses a benign nonuniversal assignment of supersymmetry-breaking scalar masses, which may have interesting low-energy experimental consequences.

scholarly journals Supersymmetry breaking, brane dynamics and Swampland conjectures

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Ivano Basile
Keyword(s):  
Supersymmetry Breaking ◽  
Effective Charge ◽  
Qualitative Agreement ◽  
Heterotic String ◽  
The Other ◽  
String Amplitude ◽  
String Models ◽  
Weak Gravity

Abstract We investigate interactions between branes of various dimensions, both charged and uncharged, in three non-supersymmetric string models. These include the USp(32) and U(32) orientifold projections of the type IIB and type 0B strings, as well as the SO(16)×SO(16) projection of the exceptional heterotic string. The resulting ten-dimensional spectra are free of tachyons, and the combinations of branes that they contain give rise to rich and varied dynamics. We compute static potentials for parallel stacks of branes in three complementary regimes: the probe regime, in which one of the two stacks is parametrically heavier than the other, the string-amplitude regime, in which both stacks are light, and the holographic regime. Whenever comparisons are possible, we find qualitative agreement despite the absence of supersymmetry. For charged branes, our analysis reveals that the Weak Gravity Conjecture is satisfied in a novel way via a renormalization of the effective charge-to-tension ratio.

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 Local string models of soft supersymmetry breaking

2004 ◽  
Vol 2004 (06) ◽  
pp. 007-007 ◽  
Author(s):  
Albion Lawrence ◽  
John McGreevy
Keyword(s):  
Supersymmetry Breaking ◽  
Soft Supersymmetry Breaking ◽  
String Models

scholarly journals PROGRESS IN WEAKLY COUPLED STRING PHENOMENOLOGY

2002 ◽  
Vol 17 (supp01) ◽  
pp. 70-83
Author(s):  
MARY K. GAILLARD
Keyword(s):  
String Theory ◽  
Supersymmetry Breaking ◽  
Particle Physics ◽  
Specific Model ◽  
Heterotic String ◽  
Particle Spectrum ◽  
Heterotic String Theory ◽  
Hidden Sector ◽  
String Phenomenology ◽  
Weakly Coupled

The weakly coupled vacuum of E8 ⊗ E8 heterotic string theory remains an attractive scenario for particle physics. The particle spectrum and the issue of dilaton stabilization are reviewed. A specific model for hidden sector condensation and supersymmetry breaking, that respects known constraints from string theory, is described, and its phenomenological and cosmological implications are discussed.

Sign in / Sign up

Export Citation Format

Share Document