119287976
Solving the Effective Field Equations for the Newtonian Potential
Loop corrections to the gravitational potential are usually inferred from scattering amplitudes, which seems quite different from how the linearized Einstein equations are solved with a static, point mass to give the classical potential. In this study we show how the Schwinger–Keldysh effective field equations can be used to compute loop corrections to the potential in a way which parallels the classical treatment. We derive explicit results for the one-loop correction from the graviton self-energy induced by a massless, minimally coupled scalar.
118606531
Quantum gravity corrections to the conformally coupled scalar self-mass-squared on de Sitter background
We evaluate one loop quantum gravity corrections to the conformally coupled (CC) scalar self-mass-squared on a locally de Sitter background. In this paper we consider only the conformal-conformal interaction part of the self-mass-squared. This complements the minimal-minimal part worked out in the previous paper [E. O. Kahya and R. P. Woodard, Phys. Rev. D 76, 124005 (2007), arXiv: 0709.0536], and we will add the minimal-conformal part in a follow-up paper to complete the full self-mass-squared at one loop order. The computation is performed using dimensional regularization and the results are fully renormalized by absorbing divergences with counterterms. The finite results can give rise to quantum corrections to the CC scalar mode functions and therefore to their power spectra.
2323759
Orbifold GUT inflation
We consider a scenario of cosmological inflation coming from a grand unified theory in higher-dimensional orbifold. Flatness of the potential is automatically guaranteed in this orbifold set-up thanks to the nonlocality of the Wilson line on higher dimensions and the local quantum gravitational corrections are exponentially suppressed. The spectral index of scalar perturbation () and a significant production of gravitational waves are predicted () in the perturbative regime of gauge interaction (1/g4 = (5–20) × 2πRMPl) where the size of compactification is constrained (–45) by the measurement of the scalar power spectrum ().
14552682
Probing large extra dimensions with spin configuration of top quark pair production at the JLC
We explore signatures of large extra dimensions with a polarized electron/positrn beam at the Joint Linear Collider (JLC). We point out that spin informations can be useful to study indirect signals for large extra dimensions due to spin-2 nature of Kaluza-Klein gravitons. The spin configurations of the top quark pair production at e + e and γγ collisions provide an unique testing ground to search for effects of the large extra dimensions. Especially we show the forward-backward ~
13907644
Neutralino nucleus elastic cross-section in the minimal supersymmetric standard model with explicit CP violation
We study the elastic scattering of the lightest neutralino with a nucleus in the framework of the minimal supersymmetric standard model (MSSM) with explicit flavor preserving CP violation, including the one-loop CP-violating neutral Higgs-boson mixing effects induced dominantly by the CP phases in the top and bottom (s)quark sectors. We construct the most general form of the effective Lagrangian for the neutralino-nucleus scattering in the limit of vanishing momentum transfers and then we perform a comprehensive analysis of the effects of the complex CP phases on the mass spectra of the lightest neutralino, neutral Higgs bosons, and top squarks, and on the spin-dependent and spin-independent neutralino-nucleus scattering cross section for three nucleus targets F, Si, and Ge. The CP phases can reduce or enhance the neutralino-nucleus cross sections significantly, depending on the values of the real parameters in the MSSM.
119164286
Exact 4-point scattering amplitude of the superconformal Schrödinger Chern-Simons theory
We consider the non-relativistic superconformal U(N) × U(N) Chern-Simons theory with level (k,−k) possessing fourteen supersymmetries. We obtain an exact four-point scattering amplitude of the theory to all orders in 1/N and 1/k and prove that the scattering amplitude becomes trivial when k = 1 and 2. We confirm this amplitude to one-loop order by using an explicit field theoretic computation and show that the beta function for the contact interaction vanishes to the one-loop order, which is consistent with the quantum conformal invariance of the underlying theory.
11001564
Inflation by non-minimal coupling
Inflationary scenarios based on simple non-minimal coupling a2R and its generalizations are studied. Generalizing the form of non-minimal coupling to K()R with an arbitrary function K(), we show that the flat potential is still obtainable when V ()/K2() is asymptotically constant. Very interestingly, if the ratio of the dimensionless self-coupling constant (λ) of the inflaton field and the non-minimal coupling constant (a) is small, , the cosmological observables for general monomial cases (K~am, V~λ2m) are in good agreement with recent observational data.