String Theory Vacua in Four Dimensions: from Particle Physics to Cosmology
Final Report Abstract
We investigated four dimensional string theory vacua in view of their validity as unified description of particle physics and cosmology. We developed D-brane model building tools for favourable corners of the Type II string theory landscape in a combination of topological/geometric and Conformal Field Theory (CFT) techniques. Amongst others, we found classes of MSSM-like and GUT-like three-generation models on orbifolds/orientifolds with factorised tori and showed how non-factorisable toroidal orbifolds/orientifolds can be rewritten in terms of factorisable tori with some additional shift symmetry. The latter allows to extend the known CFT techniques and thereby gain information about the spectrum and low-energy effective field theory well beyond the generally evoked SUGRA approximation. Our models constitute the first explicit realisation of the (dual to the) LARGE volume scenario at tree-level, where, however, we find that one-loop corrections to the gauge couplings crucially depend on all possible stringy winding and Kaluza-Klein modes, which severely constrain the physical reach of exponentially LARGE compact directions. We found that the QCD axion is naturally realised in the open string sector of stringy particle physics models. The string theoretic origin of the U (1)P Q charge from the two endpoints of an open string provides an important selection rule on possible charge assignments and couplings to the SM sector. The origin of each term in the Higgs-axion potential can be traced back. Open and closed string axions naturally mix, with the SUGRA approximation challenged if one demands an axion decay constant close to or above the phenomenologically favoured Planck scale. Upon studying deformations of orbifold singularities using the hypersurface formalism, we found that D-branes coupling in an orientifold-odd way to the singularity will stabilise the corresponding modulus at the orbifold point, even in the absence of the customarily postulated closed string background fluxes. Orientifold-even couplings of D-branes lead to modifications of the associated tree-level gauge couplings upon deformation, which result in distinctions of four-dimensional string theory vacua which agree at the orbifold point.
Publications
- “D6-brane model building on Z2 ×Z6 : MSSM-like and left-right symmetric models”. Nucl. Phys. B901 (2015) 139-215
J. Ecker, G. Honecker, W. Staessens
(See online at https://doi.org/10.1016/j.nuclphysb.2015.10.009) - “Deformations on Tilted Tori and Moduli Stabilisation at the Orbifold Point”. JHEP 1511 (2015) 019
M. Blaszczyk, G. Honecker, I. Koltermann
(See online at https://doi.org/10.1007/JHEP11(2015)019) - “Deforming D-brane models on T 6 /(Z2 × Z2M ) orbifolds”. Fortsch. Phys. 64 (2016) 412-413
I. Koltermann, M. Blaszczyk, G. Honecker
(See online at https://dx.doi.org/10.1002/prop.201500073) - “From Stringy Particle Physics to Moduli Stabilisation and Cosmology”. Fortsch. Phys. 64 (2016) 380-384
G. Honecker
(See online at https://dx.doi.org/10.1002/prop.201500064) - “From Type II string theory toward BSM/dark sector physics”. Int. J. Mod. Phys. A31 (2016) no.34, 1630050
G. Honecker
(See online at https://doi.org/10.1142/S0217751X16300507) - “Model building on the non-factorisable type IIA T 6 /(Z4 × ΩR) orientifold”. Fortsch. Phys. 64 (2016) 416-417
A. Seifert, G. Honecker
(See online at https://dx.doi.org/10.1002/prop.201500071) - “Towards geometric D6-brane model building on non-factorisable toroidal Z4 - orbifolds”. JHEP 1608 (2016) 062
M. Berasaluce-González, G. Honecker, A. Seifert
(See online at https://doi.org/10.1007/JHEP08(2016)062) - “Deformations, Moduli Stabilisation and Gauge Couplings at One-Loop”. JHEP 1704 (2017) 023
G. Honecker, I. Koltermann, W. Staessens
(See online at https://doi.org/10.1007/JHEP04(2017)023) - “Massless Spectra and Gauge Couplings at One-Loop on Non-Factorisable Toroidal Orientifolds”. Nucl.Phys. B926 (2018) 112-166
M. Berasaluce-González, G. Honecker, A. Seifert
(See online at https://doi.org/10.1016/j.nuclphysb.2017.10.023)
