Running inflation with unitary Higgs

We consider the renormalization group(RG) improved inflaton potential in unitarized Higgs inflation where the original Higgs inflation is unitarized by the addition of a real singlet scalar of sigma-model type. The sigma field coupling to the Higgs, which is introduced to reproduce a large non-minimal coupling of the Higgs below the sigma scalar threshold, also improves the Standard Model vacuum stability due to the RG running. Furthermore, the same sigma field coupling determines the reheating temperature or the number of efoldings. Considering the uncertainties in the number of efoldings in the model, we show that the loop-corrected spectral index and tensor-to-scalar ratio are consistent with nine-year WMAP and new Planck data within 1sigma.Comment: 19 pages, 8 figures, version to appear in Phys. Lett. B, typos correcte

Gauge Coupling Unification in Six Dimensions

We compute the one-loop gauge couplings in six-dimensional non-Abelian gauge theories on the T^2/Z_2 orbifold with general GUT breaking boundary conditions. For concreteness, we apply the obtained general formulae to the gauge coupling running in a 6D SO(10) orbifold GUT where the GUT group is broken down to the standard model gauge group up to an extra U(1). We find that the one-loop corrections depend on the parity matrices encoding the orbifold boundary conditions as well as the volume and shape moduli of extra dimensions. When the U(1) is broken by the VEV of bulk singlets, the accompanying extra color triplets also affect the unification of the gauge couplings. In this case, the B-L breaking scale compatible with the gauge coupling unification is sensitive to the change of the compactification scales.Comment: 32 pages, 4 figures, errors in the KK sums changing the consequent discussion on the 5D limit correcte

Reheating the Universe at Criticality

We present the general discussion on the inflection point inflation with small or large inflaton fields and show the effects of reheating dynamics on the inflationary predictions. In order to compare the model predictions with precisely measured CMB anisotropies and constrain the inflation models, the knowledge of the reheating dynamics is required. Inflection point inflation extended to the trans-Planckian regime can accommodate a sizable tensor-to-scalar ratio at the detectable level in the future CMB experiments.Comment: 6 pages, 2 figures, To appear in the proceedings of CosPA 2015 conferenc

Softness of Supersymmetry Breaking on the Orbifold T2/Z2T^2/Z_2

We consider supersymmetry breaking due to a Scherk-Schwarz twist or localized mass terms in 6d ${\cal N}=1$ supersymmetric gauge theory compactified on the orbifold $T^2/Z_2$. We show that the Scherk-Schwarz breaking in 6d is equivalent to the localized breaking with mass terms along the lines in extra dimensions. In the presence of the considered supersymmetry breaking, we find that there arises a finite one-loop mass correction to a brane scalar due to the KK modes of bulk gauge fields.Comment: JHEP style file of 16 pages, no figures, published versio

Models for SIMP dark matter and dark photon

We give a review on the SIMP paradigm and discuss a consistent model for SIMP dark mesons in the context of a dark QCD with flavor symmetry. The $Z'$-portal interaction is introduced being compatible with stable dark mesons and is responsible for making the SIMP dark mesons remain in kinetic equilibrium with the SM during the freeze-out process. The SIMP parameter space of the $Z'$ gauge boson can be probed by future collider and direct detection experiments.Comment: 4 pages, no figures, To appear in the proceedings of PPC 2015 conference, Deadwood, South Dakota, US

Gauged U(1)U(1) Clockwork Theory

We consider the gauged $U(1)$ clockwork theory with a product of multiple gauge groups and discuss the continuum limit of the theory to a massless gauged $U(1)$ with linear dilaton background in five dimensions. The localization of the lightest state of gauge fields on a site in the theory space naturally leads to exponentially small effective couplings of external matter fields localized away from the site. We discuss the implications of our general discussion with some examples, such as mediators of dark matter interactions, flavor-changing $B$-meson decays as well as D-term SUSY breaking.Comment: 22 pages, 2 figures, Expanded discussion on dark matter mediator, To be published in Physics Letters

Flattening the inflaton potential beyond minimal gravity

We review the status of the Starobinsky-like models for inflation beyond minimal gravity and discuss the unitarity problem due to the presence of a large non-minimal gravity coupling. We show that the induced gravity models allow for a self-consistent description of inflation and discuss the implications of the inflaton couplings to the Higgs field in the Standard Model.Comment: 5 pages, Prepared for the proceedings of the 13th International Conference on Gravitation, 3-7 July 201