118400868
Large non-Gaussianity in non-minimal inflation
We consider a simple inflation model with a complex scalar field coupled to gravity non-minimally. Both the modulus and the angular directions of the complex scalar are slowly rolling, leading to two-field inflation. The modulus direction becomes flat due to the non-minimal coupling, and the angular direction becomes a pseudo-Goldstone boson from a small breaking of the global U(1) symmetry. We show that large non-Gaussianity can be produced during slow-roll inflation under a reasonable assumption on the initial condition of the angular direction. This scenario may be realized in particle physics models such as the Standard Model with two Higgs doublets.
14096456
Wave function of the radion in the brane background with a massless scalar field and a self-tuning problem
We consider flat solutions in a brane world model with a massless scalar field appearing in 5D ${H}_{\mathrm{MNPQ}}^{2}.$ Since those solutions have naked bulk singularities or are such that the 4D Planck mass is divergent, we should have a compact extra dimension, the size of which is then fixed by brane tension(s) and the bulk cosmological constant. By inspecting scalar perturbations around the flat solutions, we find that there is no zero mode for the radion and radion modes have only positive masses. This result confirms the fact that the radius of the extra dimension cannot be adjusted independently of the parameters of the model, and thus that the model considered does not solve the problems encountered in other approaches to the self-tuning of the cosmological constant.
119248157
Vector Higgs-portal dark matter and the invisible Higgs
The Higgs sector of the Standard Model offers a unique probe of the hidden sector. In this work, we explore the possibility of renormalizable Higgs couplings to the hidden sector vector fields which can constitute dark matter (DM). Abelian gauge sectors with minimal field content, necessary to render the gauge fields massive, have a natural Z2 parity. This symmetry ensures stability of the vector fields making them viable dark matter candidates, while evading the usual electroweak
14725085
Various modified solutions of the Randall–Sundrum model with the Gauss–Bonnet interaction
Abstract The Gauss–Bonnet interaction is the only consistent quadratic interaction below the Planck scale in the Randall–Sundrum compactification. We study various static and inflationary solutions including this Gauss–Bonnet interaction.
119351828
Self-tuning solution of the cosmological constant problem with antisymmetric tensor field
We obtain the self-tuning solution of the cosmological constant problem in the Randall-Sundrum model with introducing a three-index antisymmetric tensor field of a specific form in the Lagrangian. We also consider the dual description of the self-tuning solution.
119217517
U(1)R mediation from the flux compactification in six dimensions
We consider a supersymmetric completion of codimension‐two branes with nonzero tension in a 6D gauged supergravity. As a consequence, we obtain the football solution with 4D Minkowski space as a new supersymmetric background that preserves 4D N = 1 SUSY. In the presence of brane multiplets, we derive the 4D effective supergravity action for the football background and show that the remaining modulus can be stabilized by a bulk non‐perturbative correction with brane uplifting potentials at a zero vacuum energy. We find that the U(1)R mediation can be a dominant source of SUSY breaking for a brane scalar with nonzero R charge.
118567798
Long-range interaction effects on neutrino oscillation
Motivated by the recent anomaly in the muon neutrino and anti-muon neutrino disappearance experiments, we consider a long-range interaction with an extremely light gauge boson and extraordinarily weak coupling. A long-range interaction, consistent with current bounds, could have very pronounced effects on atmospheric neutrino disappearance that will be studied with the IceCube DeepCore array, currently in operation, and can have a significant effect on future high-precision long-baseline oscillation experiments. This invited talk was based on the paper with Hooman Davoudiasl and William Marciano [1].
119213185
The superhorizon test of future B-mode experiments
Inflation predicts B-mode polarization with correlations that span superhorizon scales at recombination. In contrast, the correlations set up by causal sources, such as phase transitions or defects, necessarily vanish on superhorizon scales. Motivated by BICEP2's B-mode detection, we consider the prospects for measuring the inflationary superhorizon signature in future observations. We explain that the finite resolution of an experiment and the filtering of the raw data induces a transfer of spurious subhorizon power to superhorizon scales, and describe ways to correct for it. We also provide a detailed treatment of possible sources of noise in the measurement. Finally, we present forecasts for the detectability of the signal with future CMB polarization experiments.
21933383
Fourth generation parity.
We present a very simple fourth generation (4G) model with an abelian gauge interaction under which only the 4G fermions have nonzero charge. The U(1) gauge symmetry can have a Z2 residual discrete symmetry (4G parity), which can stabilize the lightest 4G particle (L4P). When the 4G neutrino is the L4P, it would be a neutral and stable particle and the other 4G fermions would decay into the L4P, leaving the trace of missing energy plus the standard model fermions. Because of the new symmetry, the 4G particle creation and decay modes are different from those of the sequential 4G model, and the 4G particles can be appreciably lighter than typical experimental bounds.
119207256
Dileptons and four leptons at Z′ resonance in the early stage of the LHC
Abstract The LHC era just began. The first discovery at the LHC experiment would be arguably a new resonance pole at TeV scale, if it exists. While the discovery of the Z ′ would be exciting by itself, it may also suggest what other new physics signals should be looked for while the LHC experiment is still at its early stage. We argue that the four lepton resonance at the Z ′ pole is a well-motivated and promising signal especially in supersymmetry framework, which can serve as a supersymmetry search scheme even in the early stage of the LHC experiment.
16281369
Common gauge origin of discrete symmetries in observable sector and hidden sector
An extra Abelian gauge symmetry is motivated in many new physics models in both supersymmetric and nonsupersymmetric cases. Such a new gauge symmetry may interact with both the observable sector and the hidden sector. We systematically investigate the most general residual discrete symmetries in both sectors from a common Abelian gauge symmetry. Those discrete symmetries can ensure the stability of the proton and the dark matter candidate. A hidden sector dark matter candidate (lightest U-parity particle or LUP) interacts with the standard model fields through the gauge boson Z' which may selectively couple to quarks or leptons only. We make a comment on the implications of the discrete symmetry and the leptonically coupling dark matter candidate, which has been highlighted recently due to the possibility of the simultaneous explanation of the DAMA and the PAMELA results. We also show how to construct the most general U(1) charges for a given discrete symmetry, and discuss the relation between the U(1) gauge symmetry and R-parity.