14527961
Moduli evolution in the presence of matter fields and flux compactification
We provide a detailed analysis of the dynamics of moduli fields in the KKLT scenario coupled to a Polonyi field, which plays the role of a hidden matter sector field. It was previously shown that such matter fields can uplift AdS vacua to Minkowski or de Sitter vacua. Additionally, we take a background fluid into account (which can be either matter or radiation), which aids moduli stabilization. Our analysis shows that the presence of the matter field further aids stabilization, due to a new scaling regime. We study the system both analytically and numerically.
14862395
Softness of brane-localized supersymmetry breaking on orbifolds
Abstract We consider the brane-localized supersymmetry breaking in 5D compactified on S 1 / Z 2 . In case of a bulk gaugino with arbitrary brane masses for its even and odd modes, we find the mass spectrum and the wave functions of gaugino. We show that the gaugino masses at the distant brane are soft in the usual sense in the effective field theory with zero modes of bulk gauge fields and they are also extremely soft in view of the one-loop finite mass of a brane scalar in the KK regularization.
119116990
Vector Higgs-portal dark matter and Fermi-LAT gamma ray line
We propose a renormalizable model for vector dark matter with extra U(1) gauge symmetry, which is broken by the VEV of a complex singlet scalar. When the singlet scalar has a quartic coupling to a heavy charged scalar, the resonance effect enhances the annihilation cross section of vector dark matter into two photons such that Fermi-gamma ray line at about 130 GeV is obtained. In the presence of a tiny mixing between the singlet scalar and the Standard Model Higgs doublet, the relic density is determined dominantly by WW/ZZ and two-photon channels near the resonance pole of the singlet scalar. We also show that various phenomenological bounds coming from the Higgs to diphoton decay rate, precision data and collider searches for the charged scalar and vacuum stability are satisfied in the model.
119366917
Double suppression of FCNCs in supersymmetric models
A mechanism for double suppression of flavor-changing neutral currents (FCNCs) and CP violating phases in supersymmetric models is suggested. At M{sub SUSY} they are suppressed due to a nonabelian discrete flavor symmetry, and the infrared attractive force of gauge interactions in extra dimensions are used to suppress them at the compactification scale. We present a concrete model, which is a simple extension of S{sub 3} invariant minimal supersymmetric standard model, where only SU(2){sub L} and SU(3){sub C} gauge multiplets are assumed to propagate in the bulk. We find that a disorder of 2 orders of magnitude in soft supersymmetry breaking parameters above the compactification scale may be allowed to satisfy experimental constraints on FCNC processes and CP violating phenomena.
42769057
Conditions for large non-Gaussianity in two-field slow-roll inflation
We study the level of primordial non-Gaussianity in slow-roll two-field inflation. Using an analytic formula for the non-linear parameter fNL in the case of a sum or product separable potential, we find that it is possible to generate significant non-Gaussianity even during slow-roll inflation with Gaussian perturbations at Hubble exit. In this paper we give the general conditions for obtaining large non-Gaussianity and calculate the level of fine-tuning required to obtain this. We present explicit models in which the non-Gaussianity at the end of inflation can exceed the current observational bound of .
118604242
Quasar polarization with two axionlike particles
Abstract Recently, it was shown, that the absence of circular polarization of visible light from quasars, severely constrains the interpretation of axion like particles (ALPs) as a solution for the generation of the linear polarization. Furthermore, the new observation of the linear polarization in the radio wavelength from quasars, similar to the earlier observation performed in the optical band, makes the ALPs scenario inconsistent with at least one of the two observations. In this study we extend this scenario, to two axion like particles, one scalar and another pseudoscalar. We find, that the effects from scalar and pseudoscalar cancel out each other, thereby suppressing the circular polarization, while preserving consistent linear polarization, as observed in both visible and radio waves bands.
119286463
Peccei-Quinn NMSSM in the light of 125 GeV Higgs
A bstractWe study the phenomenology of the Peccei-Quinn invariant extension of the next-to-minimal supersymmetric standard model (NMSSM) in view of the recent discovery of a 125 GeV Higgs boson. The minimal model having no quadratic and cubic terms of the NMSSM singlet field predicts a light singlino-like lightest supersymmetric particle (LSP). The model is strongly constrained by the Higgs invisible decay and the dark matter characteristic of the LSP, while some constraints can be relaxed by assuming that the saxion, the CP-even companion of the axion in the Peccei-Quinn sector, causes a late-time entropy production diluting the thermal LSP density. The collider signal of the model contains multi-jet and h/W/Z plus missing energy, which can be discovered in the early stage of the 14 TeV LHC running.
8875159
Higher order couplings in magnetized brane models
We compute three-point and higher order couplings in magnetized brane models. We show that higher order couplings are written as products of three-point couplings. This behavior is the same as higher order amplitudes by conformal field theory calculations e.g. in intersecting D-brane models.
119201914
Extended gauge symmetries in F-theory
We study gauge symmetry in F-theory in light of global aspects. For this, we consider not only a simple (local) group, but also a semi-simple group with Abelian factors. Once we specify the complete gauge group by decomposing the discriminant, analogous to arranging 7-branes, we can derive the matter contents, their localization and the relation to enhanced groups. Global constraints coming from Calabi-Yau conditions and anomaly cancellations imply a unified group. The semisiple group shows explicit formation of matter curves and nontriviality of its embedding into exceptional group. Also the dual heterotic string vacua with line bundles provide a guide on the unification.
54193494
Sparticle spectrum of large volume compactification
We examine the large volume compactification of Type IIB string theory or its F theory limit and the associated supersymmetry breakdown and soft terms. It is crucial to incorporate the loop-induced moduli mixing, originating from radiative corrections to the Kähler potential. We show that in the presence of moduli mixing, soft scalar masses generically receive a D-term contribution of the order of the gravitino mass m3/2 when the visible sector cycle is stabilized by the D-term potential of an anomalous U(1) gauge symmetry, while the moduli-mediated gaugino masses and A-parameters tend to be of the order of m3/2/8π2. It is noticed also that a too large moduli mixing can destabilize the large volume solution by making it a saddle point.
119181837
Axial charges of the nucleon and N* resonances
The axial charges of the nucleon and the well-established N * resonances are studied within a consistent framework. For the first time the axial charges of the N * resonances are produced for the relativistic constituent quark model. The axial charge of the nucleon is predicted close to experiment, and the ones of N * (1535) and N * (1650), the only cases where such a comparison is possible, agree well with results from quantum chromodynamics on the lattice that have recently become available. The relevance of the magnitudes of the N * axial charges for the low-energy behavior of quantum chromodynamics is discussed.