The observed value of the Higgs boson mass indicates that the Higgs potential becomes small and flat at the scale around ${10}^{17}\text{ }\text{ }\mathrm{GeV}$. Having this fact in mind, we reconsider the Higgs inflation scenario proposed by Bezrukov and Shaposhnikov. It turns out that the nonminimal coupling $$\xi${}$ of the Higgs squared to the Ricci scalar can be smaller than 10. For example, $$\xi${}=7$ corresponds to the tensor-to-scalar ratio $r$\simeq${}0.2$, which is consistent with the recent observation by BICEP2.

Hyper-Kamiokande consists of two identical water-Cherenkov detectors of total 520 kt, with the first one in Japan at 295 km from the J-PARC neutrino beam with 2.5|$^\circ$| off-axis angles (OAAs), and the second one possibly in Korea at a later stage. Having the second detector in Korea would benefit almost all areas of neutrino oscillation physics, mainly due to longer baselines. There are several candidate sites in Korea with baselines of 1000–1300 km and OAAs of 1|$^\circ$|–3|$^\circ$|⁠. We conducted sensitivity studies on neutrino oscillation physics for a second detector, either in Japan (JD |$\times$| 2) or Korea (JD + KD), and compared the results with a single detector in Japan. Leptonic charge–parity (CP) symmetry violation sensitivity is improved, especially when the CP is non-maximally violated. The larger matter effect at Korean candidate sites significantly enhances sensitivities to non-standard interactions of neutrinos and mass ordering determination. Current studies indicate the best sensitivity is obtained at Mt. Bisul (1088 km baseline, |$1.3^\circ$| OAA). Thanks to a larger (1000 m) overburden than the first detector site, clear improvements to sensitivities for solar and supernova relic neutrino searches are expected.

The observed Higgs mass $M_H=125.9\pm 0.4\mathrm{GeV}$ leads to the criticality of the standard model, that is, the Higgs potential becomes flat around the scale $10^{17–18}\mathrm{GeV}$ for the top mass 171.3 GeV. Earlier we proposed a Higgs inflation scenario in which this criticality plays a crucial role. In this paper, we investigate the detailed cosmological predictions of this scenario in light of the latest Planck and BICEP2 results. We also consider the Higgs portal scalar dark matter model, and compute the Higgs one-loop effective potential with the two-loop renormalization group improvement. We find a constraint on the coupling between the Higgs boson and dark matter which depends on the inflationary parameters.

The observed neutrino oscillation data might be explained by new physics at a TeV scale, which is testable in the future experiments. Among various possibilities, the low-energy Higgs triplet model is a prime candidate of such new physics since it predicts clean signatures of lepton flavor violating processes directly related to the neutrino masses and mixing. It is discussed how various neutrino mass patterns can be discriminated by examining the lepton flavor violating decays of charged leptons as well as the collider signatures of a doubly charged Higgs boson in the model

Superheavy dark matter may show its presence in high-energy neutrino signals detected on Earth. From the latest results of IceCube, we could set the strongest lower bound on the lifetime of dark matter beyond 100 TeV around ${10}^{28}s$. The excess around a PeV is noticed and may be interpreted as the first signal of dark matter even though further confirmation and dedicated searches are invited.