Related papers: D-branes and the Standard Model
In this brief report, we summarize our recent studies in brane cosmology in both string theory and M-Theory on $S^{1}/Z_{2}$. In such setups, we find that the radion is stable and its mass, with a very conservative estimation, can be of the…
Assuming the existence of a supersymmetric U(1) gauge factor at the TeV energy scale (motivated either by the superstring-inspired E_6 model or low-energy electroweak phenomenology), several important consequences are presented. The…
Supersymmetry solves the gauge hierarchy problem of the Standard Model if the masses of supersymmetric partners of the SM particles are close to the weak scale. In this thesis, we argue that the supersymmetric Standard Model, while avoiding…
We discuss IR limit of four-fermion scattering amplitudes in braneworld models including intersecting-branes and SUSY SU(5) GUT version of it. With certain compactification where instanton effect is negligible, grand unification condition…
In the mapping from four-dimensional gauge theories to string theory in $AdS$ space, many features of gauge theory can be described by branes wrapped in different ways on $\S^5$, $\RP^5$, or subspaces thereof. These include a baryon vertex…
We present an $E_6$ Grand Unified model with a realistic pattern of fermion masses. All standard model fermions are unified in three fundamental 27-plets (i.e. supersymmetry is not invoked), which involve in addition right handed neutrinos…
Some of the four-dimensional Superstring solutions provide a consistent framework for a Supersymmetric Unification of all interactions including gravity. A class of them extends successfully the validity of the standard model up to the…
A possible minimal model of the gauge-Higgs unification based on the higher dimensional spacetime M^4 X (S^1/Z_2) and the bulk gauge symmetry SU(3)_C X SU(3)_W X U(1)_X is constructed in some details. We argue that the Weinberg angle and…
The idea of the self-breaking of the standard model gauge symmetry is applied to a gauge theory in a warped space. We systematically examine the gauge couplings of bulk and brane fermions. The constraint on the masses of bulk fermions is…
It is shown how two-dimensional states corresponding to D-branes arise in orbifolds of topologically massive gauge and gravity theories. Brane vertex operators naturally appear in induced worldsheet actions when the three-dimensional gauge…
Some of basic problems in neutrino physics such as new energy scales, the enormous gap between neutrino masses and the lightest charged fermion mass, possible existance of sterile neutrinos in eV mass range are studied in the local gauge…
We construct D-branes in a left-right asymmetrically gauged WZW model, with the gauge subgroup embedded differently on the left and the right of the group element. The symmetry-preserving boundary conditions for the group-valued field $g$…
The Standard Model has three generations of fermions and although it does not contain any explicit reason for this, the existence of additional generations is now very constrained by experiment. Present measurements are saturating…
We investigate the proposed ``D-brane alternative'' to the MSSM model (DMSSM) which is a type II B string orientifold model with N=1 supersymmetry, three generations and a $SU(3)\times SU(2)_R\times SU(2)_L \times U(1)_{B-L}$ gauge group.…
Intersecting D-brane models in string theory can naturally support the gauge and matter content of left-right symmetric extensions of the Standard Model with gauge symmetry SU(3)_c x SU(2)_L x SU(2)_R x U(1)_{B-L}. Considering such models…
We study several aspects of supersymmetric models with a $U(1)_R$ symmetry where the Higgs doublet is identified with the superpartner of a lepton. We derive new, stronger bounds on the gaugino masses based on current measurements, and also…
Dvali and Shifman have proposed a field-theoretic mechanism for localizing gauge fields to "branes" in higher dimensional spaces using confinement in a bulk gauge theory. The resulting objects have a number of qualitative features in common…
In the standard model, the electroweak Z-string can end on a Nambu monopole, whose mass is calculated to be 689 GeV from the current precise experimental data assuming the new particle with mass 125 GeV to be the Higgs boson. We study an…
We construct extensions of the Standard Model in which the gauge symmetries and supersymmetry prevent the dangerously large effects that may potentially be induced in a supersymmetric standard model by Planck scale physics. These include…
The proposed work is an extension of the Standard Model, where we have introduced two gauge symmetries, i.e., $U(1)_{B-L}$ and $U(1)_{L_e-L_\mu}$ to study neutrino phenomenology, muon, and electron $(g-2)$ as well as leptogenesis using the…