119338290
Neutrino Mass from R-parity Violation in Split Supersymmetry
We investigate how the observed neutrino data can be accommodated by R-parity violation in Split Supersymmetry. The atmospheric neutrino mass and mixing are explained by the bilinear parameters ξi inducing the neutrino-neutralino mixing as in the usual low-energy supersymmetry. Among various one-loop corrections, only the quark-squark exchanging diagrams involving the order-one trilinear couplings λ'i23,i32 can generate the solar neutrino mass and mixing if the scalar mass mS is not larger than 109 GeV. This scheme requires an unpleasant hierarchical structure of the couplings, e.g., λi23,i32 ~ 1, λ'i3310−4 and ξi10−6. On the other hand, the model has a distinct collider signature of the lightest neutralino which can decay only to the final states, liW(*) and νZ(*), arising from the bilinear mixing. Thus, the measurement of the ratio; Γ(eW(*)):Γ(μW(*)):Γ(τW(*)) would provide a clean probe of the small reactor and large atmospheric neutrino mixing angles as far as the neutralino mass is larger than 62 GeV.
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.
119500835
Testing Higgs triplet model and neutrino mass patterns
The observed neutrino oscillation data might be explained by new physics at a TeV scale, which is testable in the future experiments. Among various possibilities, the low-energy Higgs triplet model is a prime candidate of such new physics since it predicts clean signatures of lepton flavor violating processes directly related to the neutrino masses and mixing. It is discussed how various neutrino mass patterns can be discriminated by examining the lepton flavor violating decays of charged leptons as well as the collider signatures of a doubly charged Higgs boson in the model.
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.
16076999
Minimal extra dimensional cosmology from hidden sector gauge theory
We build a minimal cosmological model in higher dimensions based on a hidden sector gauge theory, which is less constrained by the low energy experiments. In this model we introduce the minimal non-Abelian gauge symmetry SU(2) in the fifth spatial dimension. The inflaton field which is identified as a part of higher dimensional gauge boson is protected by the gauge symmetry. Thus the inflaton potential is fully radiatively generated by the gauge self interaction alone without introducing any ad hoc field. and is flat enough to drive slow-roll inflation. We find that in the regime of perturbative gauge interaction and large compactification radius the anticipated magnitude of the curvature perturbation power spectrum and the value of the corresponding spectral index are in perfect agreement with the recent observations in a wide range of the model parameters. The model also predicts a large fraction of the gravitational waves, negligible non-Gaussianity, and high enough reheating temperature.
14695226
Rotating Black Holes at Future Colliders
We consider the production and decay of TeV-scale black holes. Evaluation of the production cross section of higher dimensional rotating black holes is made. The master field equation for general spin-$s$ fields confined on brane world is derived. For five-dimensional (Randall-Sundrum) black holes, we obtain analytic formulae for the greybody factors in low frequency expansion.
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.
96425170
Structure formation in a nonlocally modified gravity model
We study a nonlocally modified gravity model proposed by Deser and Woodard which gives an explanation for current cosmic acceleration. By deriving and solving the equations governing the evolution of the structure in the Universe, we show that this model predicts a pattern of growth that differs from standard general relativity (+dark energy) at the 10-30% level. These differences will be easily probed by the next generation of galaxy surveys, so the model should be tested shortly.
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.
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.
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.