44257648
Higgs inflation is still alive after the results from BICEP2.
The observed value of the Higgs boson mass indicates that the Higgs potential becomes small and flat at the scale around 10(17)  GeV. Having this fact in mind, we reconsider the Higgs inflation scenario proposed by Bezrukov and Shaposhnikov. It turns out that the nonminimal coupling ξ of the Higgs squared to the Ricci scalar can be smaller than 10. For example, ξ=7 corresponds to the tensor-to-scalar ratio r≃0.2, which is consistent with the recent observation by BICEP2.
118307706
Hawking radiation of mini black holes at colliders: Determination of BH evolution
In the series of papers by Ida, Oda and Park, the complete description of Hawking radiation to the brane localized Standard model fields from mini black holes in the low energy gravity scenarios are obtained. In this proceedings, we briefly review what we have learned in those papers.
14086679
Implication of Brane fluctuations to indirect collider signals
We study the effect of brane fluctuation on the indirect signals of high energy colliders. Brane fluctuation could act as a regulator of divergent expression of infinite tower of Kaluza-Klein graviton effects. The phenomenological parameter λ, introduced by Hewett, is shown to be determined in our setting, and its dramatic behaviors depending on the D = 4+δ dimensional gravitation scale MD, `softening parameter' Δ, and (s)1/2 of collider are presented. The present exclusion bounds from the processes e+e−→γγ and p→e+e−,γγ(γ) are considered within the parameter space (MD,Δ) with respect to the number of extra dimensions.
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.
119266173
Stop and Sbottom LSP with R-parity Violation
Considering a third-generation squark as the lightest supersymmetric particle (LSP), we investigate R-parity violating collider signatures with bilinear LH or trilinear LQD operators that may contribute to observed neutrino masses and mixings. Reinterpreting the LHC 7+8 TeV results of SUSY and leptoquark searches, we find that third-generation squark LSPs decaying to first- or second-generation leptons are generally excluded up to at least about 660 GeV at 95%C.L.. One notable feature of many models is that sbottoms can decay to top quarks and charged leptons that lead to a broader invariant mass spectrum and weaker collider constraints. More dedicated searches with $b$-taggings or top reconstructions are thus encouraged. Finally, we discuss that the recently observed excesses in the CMS leptoquark search can be accommodated by the decay of sbottom LSPs in the LQD$_{113+131}$ model.
119288619
Black holes and the LHC: A review
Abstract In low-scale gravity models, a particle collider with trans-Planckian collision energies can be an ideal place for producing black holes because a large amount of energy can be concentrated at the collision point, which can ultimately lead to black hole formation. In this article, the theoretical foundation for microscopic higher dimensional black holes is reviewed and the possible production and detection at the LHC is described and critically examined.
119251409
Nonlocal Gravity and Structure in the Universe
The observed acceleration of the Universe can be explained by modifying general relativity. One such attempt is the nonlocal model of Deser and Woodard. Here we fix the background cosmology using results from the Planck satellite and examine the predictions of nonlocal gravity for the evolution of structure in the Universe, confronting the model with three tests: gravitational lensing, redshift space distortions, and an estimator of gravity ${E}_{G}$ that combines spectroscopic information with lensing. Current data favor general relativity (GR) over nonlocal gravity: fixing primordial cosmology with the best fit parameters from Planck leads to weak lensing results favoring GR by 6.8 sigma; redshift space distortions measurements of the growth rate preferring GR by 7.8 sigma; and the single measurement of ${E}_{G}$ favoring GR, but by less than 1 sigma. The significance holds up even after the parameters are allowed to vary within Planck limits. The larger lesson is that a successful modified gravity model will likely have to suppress the growth of structure compared to general relativity.
21452649
Scalar Contribution to the Graviton Self-Energy during Inflation
We use dimensional regularization to evaluate the one loop contribution to the graviton self-energy from a massless, minimally coupled scalar on a locally de Sitter background. For noncoincident points our result agrees with the stress tensor correlators obtained recently by Perez-Nadal, Roura, and Verdaguer. We absorb the ultraviolet divergences using the R{sup 2} and C{sup 2} counterterms first derived by 't Hooft and Veltman, and we take the D=4 limit of the finite remainder. The renormalized result is expressed as the sum of two transverse, fourth order differential operators acting on nonlocal, de Sitter invariant structure functions. In this form it can be used to quantum correct the linearized Einstein equations so that one can study how the inflationary production of infrared scalars affects the propagation of dynamical gravitons and the force of gravity.
118577921
The volume of the past light-cone and the Paneitz operator
We study a conjecture involving the invariant volume of the past light-cone from an arbitrary observation point back to a fixed initial value surface. The conjecture is that a fourth order differential operator which occurs in the theory of conformal anomalies gives 8π when acted upon the invariant volume of the past light-cone. We show that an extended version of the conjecture is valid for an arbitrary homogeneous and isotropic geometry. First order perturbation theory about flat spacetime reveals a violation of the conjecture which, however, vanishes for any vacuum solution of the Einstein equation. These results may be significant for constructing quantum gravitational observables, for quantifying the back-reaction on spacetime expansion and for alternate gravity models which feature a timelike vector field.
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.
119239609
Alternate definitions of loop corrections to the primordial power spectra
We consider two different definitions for loop corrections to the primordial power spectra. One of these is to simply correct the mode functions in the tree order relations using the linearized effective field equations. The second definition involves the spatial Fourier transform of the 2-point correlator. Although the two definitions agree at tree order, we show that they disagree at one loop using the Schwinger-Keldysh formalism, so there are at least two plausible ways of loop correcting the tree order result. We discuss the advantages and disadvantages of each.