Richard Easther, The University of Auckland

Monodromy Inflation: Nonlinear Dynamics and Observational Status

##### I will discuss the phenomenology and observational status of monodromy inflation. This apparently simple model is based on a stringy axion associated with a weakly broken shift-symmetry. I will show that the post-inflationary dynamics may naturally contain a phase where the universe is dominated by oscillons, pseudo-stable solutions of a nonlinear scalar field theories. Conversely, the inflationary perturbations can include a superimposed “modulation”, and I will discuss current constraints on the amplitude of these modulations, derived from the WMAP and Planck datasets.

Kunio Kaneta, Kavli IPMU

Higgs pair production at the LHC and ILC as a clue to new physics

##### The measurement of the Higgs boson self-coupling is important to understand what kind of force makes the Higgs boson acquires a VEV. It is expected that Higgs cubic coupling is measured by Higgs pair production at the LHC and ILC, and the deviations from the SM in the Higgs pair production process can give us a hint of new physics beyond the SM. We consider this process from a general potential that achieves the suitable EW symmetry breaking. As an interesting example, we discuss non-perturbative Higgs model in which a runaway type of potential is used. In the model, the cross sections of pair production can be enhanced compared to the SM. We also discuss the Higgs pair production induced by a non-canonical kinetic term of Higgs field, which will be important for searching the pair production at the ILC.

Lu-Hsing Tsai, NTHU, Taiwan

Majorana neutrinos and multi-component Dark Matter Model from AMS-02 Result.

##### Recently AMS-02 gives the most accurate measurement of positron fraction in cosmic rays. The traditional astrophysical sources can not explain the excess above 10 GeV in both spectrums of total fluxes of electron/ positron by Fermi-LAT and positron fraction by AMS-02. The extra contribution from dark matter decay or annihilation could provide a promising explanation. In this talk I will show how to simultaneously explain the anomalies of Fermi-LAT and AMS-02 results by a decaying dark matter model with two dark matter components, each of which has two-body leptonic decays as the main channels. In such scenarios there also exist substructures in these spectrums. This model satisfies the constraints by the observation of diffuse gamma-rays by Fermi-LAT. We also show that heavy Majorana neutrinos could be a possible candidate for dark matter in this scenario.

Hiroyuki Ishida, Tohoku U

Baryogenesis and Dark Mmatter with Sterile Neutrinos

##### Sterile neutrinos below electroweak scale can solve baryon asymmetry of the universe, tiny neutrino masses and a candidate of dark matter at the same time. In this work, we derive the kinetic equations for density matrices with exact momentum dependence holding total lepton number conservation. We evaluate the amount of baryon number generation more accurately by these kinetic equations. Furthermore, X-ray observations give us very severe constraints on the magnitude of interaction and the range of mass of decaying strerile neutrino dark matter. However, the enough suppressed Yukawa couplings cannot be realized as long as seesaw is preserved. We call such requirement of fine tuning as “Longevity problem”. This problem can be solved by split flavor mechanism in which we introduced multiple B-L Higgs fields and a flavor symmetry. The predicted X-ray flux can be just below the current experimental bound naturally

Mitsutoshi Fujita 藤田充俊, Kavli IPMU

[Strings and Fields Group Seminar] From Maxwell-Chern-Simons theory in AdS3 towards hydrodynamics in 1 + 1 dimensions (AdS_3上のMaxwell-Chern-Simonsから1+1次元の流体力 学に向けて)

##### We study Abelian Maxwell-Chern-Simons theory in three-dimensional AdS black hole backgrounds for both integer and non-integer Chern-Simons coupling. In particular we find exact solutions in the low-frequency, low-momentum limit, ω, k << T (hydrodynamic limit). Using the holographic principle, we translate our results into correlation functions of vector and scalar operators in the dual strongly coupled

1+1-dimensional quantum

field theory with a chiral anomaly at non-zero temperature T. Starting from the conformal case we show applicability of the hydrodynamic limit and discuss extensions to the non-conformal case.

Correlation functions in the conformal case are confirmed by comparison to an exact field-theoretic computation. Also a top-down string construction is provided as the ultraviolet completion for our Maxwell-Chern-Simons actions.

Tomoya Takiwaki, National Astronomical Observatory

Three dimensional simulations of core-collapse supernovae