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.

CHIRAL ZEROMODES ON VORTEX-TYPE INTERSECTING FIVE-BRANE IN HETEROTIC STRING

2013 ◽  
Vol 21 ◽  
pp. 191-192
Author(s):  
MASAYA YATA
Keyword(s):  
Dirac Equation ◽  
String Theory ◽  
Boundary Conditions ◽  
Heterotic String ◽  
The Other ◽  
Two Dimensional ◽  
Complete Spectrum ◽  
Heterotic String Theory ◽  
Brane Solution ◽  
Opposite Chirality

We solve the gaugino Dirac equation on a smeared intersecting five-brane solution in E8 × E8 heterotic string theory to search for localized chiral zeromodes on the intersection. The background is chosen to depend on the full two-dimensional overall transverse coordinates to the branes. Under some appropriate boundary conditions, we compute the complete spectrum of zeromodes to find that, among infinite towers of Fourier modes, there exist only three localized normalizable zeromodes, one of which has opposite chirality to the other two.

scholarly journals Antitumor Trans Platinum Adducts of GMP and AMP

2000 ◽  
Vol 7 (4) ◽  
pp. 169-176 ◽  
Author(s):  
Yangzhong Liu ◽  
Maria F. Sivo ◽  
Giovanni Natile ◽  
Einar Sletten
Keyword(s):  
Antitumor Activity ◽  
Energy Minimization ◽  
Qualitative Agreement ◽  
Early Stage ◽  
2D Nmr ◽  
The Other ◽  
Coordination Geometry ◽  
Nmr Data ◽  
Monofunctional Adducts

Recently it has been shown that several analogues of the clinically ineffective trans-DDP exhibit antitumor activity comparable to that of cis-DDP. The present paper describes the binding of antitumor trans-[PtCl2(E-iminoether)2] (trans-EE) to guanosinemonophosphate (GMP) and adenosinemonophosphate (AMP). We have used HPLC and H1 and N15 NMR to characterize the different adducts. In the case of a 1:1 mixture of trans-EE and GMP, at an early stage of the reaction, a monofunctional adduct is formed which, subsequently, is partly converted into a monosolvated monofunctional species. After about 70 hours an equilibrium is established between chloro and solvato monofunctional adducts at a ratio of 30/70. In the presence of excess GMP (4:1) the initially formed monofunctional adducts react further to give two bifunctional adducts, one with the iminoether ligands in their original E configurations and the other with the iminoether ligands having one E and the other, Z configurations. The coordination geometry obtained by energy minimization calculations is in qualitative agreement with 2D NMR data.

scholarly journals A Survey of BL Herculis-Type Models

1993 ◽  
Vol 139 ◽  
pp. 277-277
Author(s):  
J. Robert Buchler ◽  
Pawel Moskalik
Keyword(s):  
Light Curve ◽  
Fundamental Mode ◽  
Qualitative Agreement ◽  
Nonlinear Behavior ◽  
The Other ◽  
Amplitude Ratios ◽  
Classical Cepheids ◽  
Dominant Feature ◽  
Stellar Masses ◽  
Pulsation Cycle

AbstractWe have studied the nonlinear behavior of several sequences of BL Herculis-type models. The question arose whether the 2:1 resonance between the fundamental mode and the second overtone would cause the same systematic variation of Fourier parameters of the pulsation cycle with period ratio P2/P0 as was seen in the classical Cepheids. We find that for the BL Her stars, the behaviour of the light-curve Fourier phases is markedly different from the Cepheid case. In particular, ϕ21 exhibits essentially a featureless, monotone increase throughout the range of P2/P0, which is in qualitative agreement with the observed trend (Petersen & Diethelm 1986). In the velocity curves, on the other hand, the 2:1 resonance is a dominant feature and the progression of the Fourier phases and the amplitude ratios is similar to those witnessed in the Cepheids. However, here the sensitivity to the stellar masses and luminosities is significantly stronger. Our results show that radial velocity observations of the BL Her stars would pinpoint the resonance and put important new constraints on the models.

scholarly journals Supersymmetry breaking warped throats and the weak gravity conjecture

2019 ◽  
Vol 2019 (4) ◽  
Author(s):  
Ginevra Buratti ◽  
Eduardo García-Valdecasas ◽  
Angel M. Uranga
Keyword(s):  
Supersymmetry Breaking ◽  
Weak Gravity

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
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