Kin-ya Oda

Bare Higgs mass at Planck scale

We compute one- and two-loop quadratic divergent contributions to the bare Higgs mass in terms of the bare couplings in the Standard Model. We approximate the bare couplings, dened at the ultraviolet cuto scale, by the MS ones at the same scale, which are evaluated by the two-loop renormalization group equations for the Higgs mass around 126 GeV in the Standard Model. We obtain the cuto scale dependence of the bare Higgs mass, and examine where it becomes zero. We nd that when we take the current central value for the top quark pole mass, 173 GeV, the bare Higgs mass vanishes if the cuto is about 10 23 GeV. With a 1.3 smaller mass, 170 GeV, the scale can be of the order of

A Holographic Dual of Bjorken Flow

We propose a consistent setup for a holographic dual of Bjorken flow of strongly coupled large-Nc N = 4 SYM-theory plasma. We employ Eddington-Finkelstein type coordinates for the dual geometry, and we propose a late-time expansion there. We construct the dual geometry order by order, and we show that the transport coefficients are determined by the regularity of the geometry. We also show that the dual geometry has an apparent horizon hence an event horizon, which covers the singularity at the origin. We prove that the dual geometry is regular at all orders under an appropriate choice of the transport coefficients. Our model is a concrete well-defined example of time-dependent AdS/CFT. Subject Index: 121, 231, 451

Rotating black holes at future colliders. II. Anisotropic scalar field emission

This is the sequel to the first paper of the series, where we have discussed the Hawking radiation from five-dimensional rotating black holes for spin 0, 1/2, and 1 brane fields in the low frequency regime. We consider the emission of a brane-localized scalar field from rotating black holes in general space-time dimensions without relying on the low frequency expansions.

Higgs inflation from standard model criticality

In this chapter, we investigate the possibility that the SM Higgs boson plays the role of an inflation in light of the discovery of the Higgs boson. In 2007, Bezurkov and Shaposhnikov first pointed out this possibility. The successful Higgs inflation is realized if the non-minimal coupling between the Higgs H and scalar curvature \(\mathcal {R}\), \(\xi |H|^2 \mathcal {R}\), is introduced. \(\xi \) is the coupling constant, and very large value, \(\xi \sim 10^5\), is required for successful inflation. However, the observation of the Higgs and determination of its mass changes the situation. As we have seen in Chap. 2, the Higgs self coupling and its beta function becomes zero at very high scale, which means that the Higgs potential is very flat around string/Planck scale. This opens up the new possibilities of the Higgs inflation, which we will present here. In Sect. 3.1, we present the general argument of the Higgs inflation above the SM cutoff \(\Lambda \). In Sect. 3.2, we show that non-minimal coupling \(\xi \) can be as small as \(\mathcal {O}(10)\).

Predictions on mass of Higgs portal scalar dark matter from Higgs inflation and flat potential

A bstractWe consider the Higgs portal Z2 scalar model as the minimal extension of the Standard Model (SM) to incorporate the dark matter. We analyze this model by using the two-loop renormalization group equations. We find that the dark matter mass is bounded to be lighter than 1000 GeV within the framework that we have proposed earlier, where the Higgs inflation occurs above the SM cutoff Λ, thanks to the fact that the Higgs potential becomes much smaller than its typical value in the SM: V ≪ Λ4. We can further fix the dark matter mass to be 400 GeV < mDM< 470 GeV if we impose that the cutoff is at the string scale Λ ~ 1017 GeV and that the Higgs potential becomes flat around Λ, as is required by the multiple point principle or by the Higgs inflation at the critical point. This prediction is testable by the dark matter detection experiments in the near future. In this framework, the dark matter and top quark masses are strongly correlated, which is also testable.

Effects of brane-flux transition on black holes in string theory

Extremal = 2 black holes in four dimensions can be described by an ensemble of D3-branes wrapped on internal supersymmetric three-cycles of Calabi-Yau threefolds on which type IIB superstring theory is compactified. We construct a similar configuration, with extra RR and NS-NS three-form fluxes being turned on. We can avoid the Freed-Witten anomaly on the D3-branes by enforcing the pullback of these extra fluxes to the D3-branes to vanish at the classical level. In the setup the D3-brane charge is not conserved since it is classified as a trivial class in twisted K-theory. Consequently, the D3-branes may disappear by encountering an instantonic D5-brane localized in time. We discuss what happens on the black hole described by such disappearing D3-branes, relying mainly on topological arguments. Especially, we argue that another RR three-form flux will be left as a lump of remnant which is localized in the uncompactified four-dimensional space-time and that it may carry the same amount of degrees of freedom to describe a black hole, in cooperation with the original NS-NS flux, after this transition of the D3-branes.

Non-minimal coupling in Higgs-Yukawa model with asymptotically safe gravity

We study the fixed point structure of the Higgs-Yukawa model, with its scalar being non-minimally coupled to the asymptotically safe gravity, using the functional renormalization group. We have obtained the renormalization group equations for the cosmological and Newton constants, the scalar mass-squared and quartic coupling constant, and the Yukawa and non-minimal coupling constants, taking into account all the scalar, fermion, and graviton loops. We find that switching on the fermionic quantum fluctuations makes the non-minimal coupling constant irrelevant around the Gaussian-matter fixed point with the asymptotically safe gravity.

Neutrino masses in the supersymmetric standard model with right-handed neutrinos and spontaneousR-parity violation

We propose an extension of the supersymmetric standard model with right-handed neutrinos and a singlet Higgs field, and study the neutrino masses in this model. The Majorana masses for the right-handed neutrinos are generated around the supersymmetry breaking scale through the vacuum expectation value of the singlet Higgs field. This model may induce spontaneous R-parity violation via the vacuum expectation value of the right-handed sneutrino. In the case, the effective theory is similar to a bilinear R-parity violating model. There are two sources for the neutrino masses: one is this bilinear R-parity breaking effect, and the other is the ordinary seesaw effect between left- and right-handed neutrinos. Combining these two effects, the hierarchical neutrino mass pattern arises even when the neutrino Yukawa matrices are not hierarchical. We acquire appropriate masses and mixings to explain both the solar and atmospheric neutrino oscillations.

A bound on universal extra dimension models from up to 2 fb−1 of LHC data at 7 TeV

Abstract The recent up to ∼ 2 fb − 1 of data from the ATLAS and CMS experiments at the CERN Large Hadron Collider at 7 TeV put an upper bound on the production cross section of a Higgs-like particle. We translate the results of the H → W W → l ν l ν and H → γ γ as well as the combined analysis by the ATLAS and CMS into an allowed region for the Kaluza–Klein (KK) mass M KK and the Higgs mass M H for all the known Universal Extra Dimension (UED) models in five and six dimensions. Our bound is insensitive to the detailed KK mass splitting and mixing and hence complementary to all other known signatures.

Minimal Higgs inflation

We consider a possibility that the Higgs field in the Standard Model (SM) serves as an inflaton when its value is around the Planck scale. We assume that the SM is valid up to an ultraviolet cutoff scale \Lambda, which is slightly below the Planck scale, and that the Higgs potential becomes almost flat above \Lambda. Contrary to the ordinary Higgs inflation scenario, we do not assume the huge non-minimal coupling, of O(10^4), of the Higgs field to the Ricci scalar. We find that \Lambda must be less than 5*10^{17}GeV in order to explain the observed fluctuation of the cosmic microwave background, no matter how we extrapolate the Higgs potential above \Lambda. The scale 10^{17}GeV coincides with the perturbative string scale, which suggests that the SM is directly connected with the string theory. For this to be true, the top quark mass is restricted to around 171GeV, with which \Lambda can exceed 10^{17}GeV. As a concrete example of the potential above \Lambda, we propose a simple log type potential. The predictions of this specific model for the e-foldings N_*=50--60 are consistent with the current observation, namely, the scalar spectral index is n_s=0.977--0.983 and the tensor to scalar ratio 0