7390821
Spectral running and non-Gaussianity from slow-roll inflation in generalized two-field models
Theories beyond the standard model such as string theory motivate low energy effective field theories with several scalar fields which are not only coupled through a potential but also through their kinetic terms. For such theories we derive the general formulae for the running of the spectral indices for the adiabatic, isocurvature and correlation spectra in the case of two-field inflation. We also compute the expected non-Gaussianity in such models for specific forms of the potentials. We find that the coupling has little impact on the level of non-Gaussianity during inflation.
119103645
New decay modes of gravitino dark matter
We consider the three-body decays of gravitino dark matter in supersymmetric scenarios with bilinear R-parity violation. In particular, gravitino decays into lW* (lff{sup '}) and {nu}Z* ({nu}ff) are examined for gravitino masses below M{sub W}. After computing the gravitino decay rates into these three-body final states and studying their dependence on supersymmetric parameters, we find that these new decay modes are often more important than the two-body decay, into a photon and a neutrino, considered in previous works. Consequently, the gravitino lifetime and its branching ratios are substantially modified, with important implications for the indirect detection of gravitino dark matter.
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.
120929987
GRAVITINO DARK MATTER AND THE IMPLICATIONS
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.
125184952
Baryon axial charges
17602810
Higher order couplings from heterotic orbifold theory
Abstract We calculate couplings of arbitrary order from correlation functions among twisted strings, using conformal field theory. Twisted strings arise in heterotic string compactified on orbifolds yielding matter fields in the low energy limit. We calculate completely the classical and the quantum amplitude including normalization, up to a contribution from Kahler potential. The classical action has saddle points which are interpreted as worldsheet instantons described by metastable untwisted strings, formed by twisted strings distributed at certain fixed points. This understanding generalizes the area rule, in the case that the locations of twisted strings do not form a polygon, and provides a general rule for calculating these kinds of instanton corrections. An interpretation of couplings involving linearly combined states is given, which commonly appear in non-prime order orbifolds. The quantum part of the amplitude is given by ratios of gamma functions with order one arguments.
4991507
Higgs phenomenology in the Peccei-Quinn invariant NMSSM
A bstractWe study the Higgs phenomenology in the Peccei-Quinn invariant NMSSM (PQ-NMSSM) where the low energy mass parameters of the singlet superfield are induced by a spontaneous breakdown of the Peccei-Quinn symmetry. In the generic NMSSM, scalar mixing among CP-even Higgs bosons is constrained by the observed properties of the SM-like Higgs boson, as well as by the LEP bound on the chargino mass and the perturbativity bound on the singlet Yukawa coupling. In the minimal PQ-NMSSM, scalar mixing is further constrained due to the presence of a light singlino-like neutralino. It is noticed that the 2σ excess of the LEP $ Zb\overline{b} $ events at $ {m_{{b\overline{b}}}} $ ≃ 98 GeV can be explained by a singlet-like 98 GeV Higgs boson in the minimal PQ-NMSSM with low tan β, stops around or below 1 TeV, and light doublet-higgsinos around the weak scale.
119250759
Flavor structure from magnetic fluxes and non-Abelian Wilson lines
We study the flavor structure of four-dimensional (4D) effective theories, which are derived from extra dimensional theories with magnetic fluxes and non-Abelian Wilson lines. We study zero-mode wave functions in generic case and compute Yukawa couplings as well as four-point couplings. In our models, we also discuss non-Abelian discrete flavor symmetries such as ${D}_{4}$, $\ensuremath{\Delta}(27)$, and $\ensuremath{\Delta}(54)$. The orbifold background is also studied.
119691200
Spectroscopy of Baryons as Relativistic Three-Quark Systems
We present results from a study of baryon spectral properties within a relativistic constituent-quark model. In particular, we demonstrate the performance of a universal quark model for all light-, strange-, and heavy-flavor baryons with regard to their spectroscopy. Thereby we produce insights into the effective interaction between constituent quarks of the various flavors up, down, strange, charm, and bottom. The relativistically invariant mass spectra are obtained by two different methods for calculating the microscopic three-quark systems: a stochastic variational method, solving the eigenvalue problem of the invariant mass operator expressed by differential equations, and a Faddeev integral-equation method, adapted to treating long-range interactions, such as the quark confinement. The corresponding results agree very well, generally within a few percents. Taking into account relativistic effects through Poincaré invariance of the mass operator, or equivalently of the Hamiltonian, turns out to be of utmost importance.