arXiv subjects

Hyung Do Kim

Publications and source records attributed to Hyung Do Kim.

44 records · Page 3Linked to original sources

arXiv2002

TeV scale 5D $SU(3)_W$ unification and the fixed point anomaly cancellation with chiral split multiplets

A possibility of 5D gauge unification of $SU(2)_L \times U(1)_Y$ in $SU(3)_W$ is examined. The orbifold compactification allows fixed points where $SU(2)_L\times U(1)_Y$ representations can be assigned. We present a few possibilities which give long proton lifetime, top-bottom mass hierarchy from geometry, and reasonable neutrino masses. In general, these {\it chiral models} can lead to fixed point anomalies. We can show easily, due to the simplicity of the model, that these anomalies are cancelled by the relevant Chern-Simons terms for all the models we consider. It is also shown that the fixed point U(1)--graviton--graviton anomaly cancels without the help from the Chern-Simons term. Hence, we conjecture that the fixed point anomalies can be cancelled if the effective 4D theory is made anomaly free by locating chiral fermions at the fixed points.

hep-th↗

arXiv2002

Top-bottom mass hierarchy, $s-μ$ puzzle and gauge coupling unification with split multiplets

A supersymmetric 5D SU(5) grand unification is considered. The SU(5) is broken down to $G_{SM}=SU(3)\times SU(2)\times U(1)$ by the $Z_2\times Z_2'$ assignment of the bulk field(s). The matter fields are located at the fixed point(s). In the bulk, a Higgs multiplet $\bar 5_H$(containing the bottom doublet $H_1$) and the SU(5) gauge multiplet are located. At one fixed point, $H_2$(the top doublet) and the standard model matter multiplets are presented. Because of the difference of the locations of $H_1$ and $H_2$, one can obtain a hierarchy between top and bottom Yukawa couplings. We also present a possibility to understand the $s-μ$ mass puzzle in this framework of the split multiplet.

hep-ph↗

arXiv2001

Softness of Scherk-Schwarz Supersymmetry Breaking

We investigate how the mass correction appears in 5-D with Scherk-Schwarz compactification and clarify whether the KK regularization is reliable method or not. In the extremely sharp cutoff limit of the 5-D regulator which preserves 5-D Lorentz invariance, we prove that the one loop correction to the mass does not depend on the ultraviolet physics for the Scherk-Schwarz breaking of supersymmetry. This is a unique property of Scherk-Schwarz breaking which is given by the boundary condition.

hep-th↗

arXiv2001

To be (finite) or not to be, that is the question "Kaluza-Klein contribution to the Higgs mass"

Recently five dimensional supersymmetric models with a Scherk-Schwarz supersymmetry breaking and a localized superpotential on a fixed-point have been constructed to yield a definite prediction for the Higgs mass. We examine this issue in detail and show that the finite one loop correction and the definite prediction for the Higgs mass are just a consequence of a special "Kaluza-Klein regularization" scheme.

hep-ph↗

arXiv2001

Brane World in Generalized Gravity

We consider Randall-Sundrum(RS) model in generalized gravities and see that the localization of gravity happens in generic situations though its effectiveness depends on the details of the configuration. It is shown that RS picture is robust against quantum gravity corrections ($ϕ\R$) as long as the correction is reasonably small. We extend our consideration to the model of scalar(dilaton) coupled gravity which leads us to the specific comparison between RS model and inflation models. The exponential and power law hierarchy in RS model are shown to correspond to the exponential and power law inflation respectively.

hep-th↗

arXiv2001

A criterion for admissible singularities in brane world

When gravity couples to scalar fields in Anti-de Sitter space, the geometry becomes non-AdS and develops singularities generally. We propose a criterion that the singularity is physically admissible if the integral of the on-shell Lagrangian density over the finite range is finite everywhere. For all classes of the singularities studied here, the criterion suggested in this paper coincides with an independent proposal made by Gubser that the potential should be bounded from above in the solution. This gives a reason why Gubser's conjecture works.

hep-th↗

arXiv1999

Inflation and Gauge Hierarchy in Randall-Sundrum Compactification

We obtain the general inflationary solutions for the slab of five-dimensional AdS spacetime where the fifth dimension is an orbifold $S^1/Z_2$ and two three-branes reside at its boundaries, of which the Randall-Sundrum model corresponds to the static limit. The investigation of the general solutions and their static limit reveals that the RS model recasts both the cosmological constant problem and the gauge hierarchy problem into the balancing problem of the bulk and the brane cosmological constants.

hep-th↗

arXiv1999

Dynamical solution to the $μ$ problem at TeV scale

We introduce a new confining force (μ-color) at TeV scale to dynamically generate a supersymmetry preserving mass scale which would replace the μparameter in the minimal supersymmetric standard model (MSSM). We discuss the Higgs phenomenology and also the pattern of soft supersymmetry breaking parameters allowing the correct electroweak symmetry breaking within the μ-color model, which have quite distinctive features from the MSSM and also from other generalizations of the MSSM.

hep-ph↗