120760093
Reason for SU(6) grand unification
Abstract An SU(6) model can naturally guarantee strong CP invariance. This also includes Georgi and Glashow's SU(5) model. The axion in this model can be either invisible or visible, depending on the symmetry breaking scheme. The invisible axion is identical to a majoron. Also, there exists a relationship between 24 H and 45 H of SU(5).
119316975
GMSB at a stable vacuum and MSSM without exotics from heterotic string
Abstract We show that it is possible to introduce the confining hidden sector gauge group SU ( 5 ) ′ with the chiral matter 10 0 ′ plus 5 ¯ 0 ′ , which are neutral under the standard model gauge group, toward a gauge mediated supersymmetry breaking (GMSB) in a Z 12 − I orbifold compactification of E 8 × E 8 ′ heterotic string. Three families of MSSM result without exotics. We also find a desirable matter parity P (or R-parity) assignment. We note that this model contains the spectrum of the Lee–Weinberg model which has a nice solution of the μ problem.
119883211
Conflicts between B-violating phenomena in supergravity models
Abstract We show that there is an incompatibility between matter stability and cosmological baryon production in standard N = 1 supergravity models. This discrepancy emerges from the bound on the reheating temperature T rh ⩽ 10 10 GeV which comes from the restriction on the gravitino decay after inflation. Some weird possibilities to bypass the controversy are also analyzed.
18138135
Neutrino masses from discrete gauge symmetries
Abstract We investigate a model with an extra Z 2 gauge symmetry in the Standard Model. The symmetry gives a structure to the mass matrix for the neutrinos. With two extra Higgs singlets and two extra singlet right-handed neutrinos we can build a model that fits the requirements of the MSW solution of the Solar neutrino problem. With a third singlet right-handed neutrino it is also possible to have a 10 eV neutrino.
14574575
Effective Gauss-Bonnet interaction in Randall-Sundrum compactification
The effective gravitational interaction below the Planck scale in the Randall-Sundrum world is shown to be the Gauss-Bonnet term. In this theory we find that there exists another static solution with a positive bulk cosmological constant. Also, there exist solutions for a positive visible sector cosmological constant, which is needed for a later Friedmann-Robertson-Walker universe.
15739165
SO(10)-like Superstring Standard Model with R-parity from the Heterotic String
We construct a supersymmetric standard model in the context of the Z_{12-I} orbifold compactification of the E_8 x E_8' heterotic string theory. The gauge group is SU(3)_c x SU(2)_L x U(1)_Y x U(1)^4 x [SO(10) x U(1)^3]' with sin^2\theta_W = 3/8. We obtain three families of SO(10) spinor-like chiral matter states, and Higgs doublets. All other extra states are exactly vector-like under the standard model gauge symmetry. There are numerous standard model singlets, many of which get VEVs such that only the standard model gauge symmetry survives and desired Yukawa couplings can be generated at lower energies. In particular, all vector-like exotic states achieve superheavy masses and the R-parity can be preserved.
122236431
A telescope for observation from space of extreme lightnings in the upper atmosphere
A new type of telescope with a wide field-of-view and functions of fast zoom-in has been introduced. Two kinds of MEMS (Micro-Electro-Mechanical Systems) micromirrors, digital and analog, are used for reflectors of the telescope, placed at different focal lengths. We apply this technology to the observation from space of TLE (Transient Luminous Events), extremely large transient sparks occurring at the upper atmosphere. TLE are one type of important backgrounds to be understood for future space observation of UHECR (Ultra-High Energy Cosmic Rays). The launch of the payload carried by a Russian microsatellite is foreseen in the middle of 2008.
54573705
Constraints on the $R$-parity violating minimal supersymmetric standard model with neutrino masses from multilepton studies at the LHC
In a recent paper, we proposed a hierarchical ansatz for the lepton-number-violating trilinear Yukawa couplings of the R-parity violating minimal supersymmetric standard model. As a result, the number of free parameters in the lepton-number-violating sector was reduced from 36 to 6. Neutrino oscillation data fixes these six parameters, which also uniquely determines the decay modes of the lightest supersymmetric particle and thus governs the collider signature at the LHC. A typical signature of our model consists of multiple leptons in the final state and significantly reduced missing transverse momentum compared to models with R-parity conservation. In this work, we present exclusion limits on our model based on multilepton searches performed at the Large Hadron Collider with 7 TeV center-of-mass energy in 2011 while accommodating a 125 GeV Higgs.
118613110
How to make a clean separation between CMB E and B modes with proper foreground masking
We investigate the E/B decomposition of CMB polarization on a masked sky. In real space, operators of E and B mode decomposition involve only differentials of CMB polarization. We may, therefore in principle, perform a clean E/B decomposition from incomplete sky data. Since it is impractical to apply second derivatives to observation data, we usually rely on spherical harmonic transformation and inverse transformation, instead of using real-space operators. In spherical harmonic representation, jump discontinuities in a cut sky produces Gibbs phenomenon, unless a spherical harmonic expansion is made up to an infinitely high multipole. By smoothing a foreground mask, we may suppress the Gibbs phenomenon effectively in a similar manner to apodization of a foreground mask discussed in other works. However, we incur foreground contamination by smoothing a foreground mask, because zero-value pixels in the original mask may be rendered non-zero by the smoothing process. In this work, we investigate an optimal foreground mask, which ensures proper foreground masking and suppresses Gibbs phenomenon. We apply our method to a simulated map of the pixel resolution comparable to the Planck satellite. The simulation shows that the leakage power is lower than unlensed CMB B mode power spectrum of tensor-to-scalar ratio r ∼ 1 × 10 −7 . We compare the result with that of the original mask. We find that the leakage power is reduced by a factor of 10 6 ∼ 10 9 at the cost of a sky fraction 0.07, and that that the enhancement is highest at lowest multipoles. We confirm that all the zero-value pixels in the original mask remain zero in our mask. The application of this method to the Planck data will improve the detectability of primordial tensor perturbation.
13970812
Probing the last scattering surface through recent and future CMB observations
We have constrained the extended (delayed and accelerated) models of hydrogen recombination, by investigating associated changes of the position and the width of the last scattering surface. Using the recently obtained CMB and SDSS data, we find that the recently derived data constraints favor the accelerated recombination model, although the other models (standard, delayed recombination) are not ruled out at 1σ confidence level. If the accelerated recombination had actually occurred in our early Universe, it is likely that baryonic clustering on small scales would have been the cause of it. By comparing the ionization history of baryonic cloud models with that of the best-fit accelerated recombination model, we find that some portion of our early Universe has baryonic underdensity. We have made a forecast for the PLANCK data constraint, which shows that we will be able to rule out the standard or delayed recombination models if the recombination in our early Universe had proceeded with α~−0.01 or lower, and residual foregrounds and systematic effects are negligible.
119077660
Parametric Tension Between Even and Odd Multipole Data of the WMAP Power Spectrum: Unaccounted Contamination or Missing Parameters?
There exists power contrast in even and odd multipoles of the WMAP power spectrum at low and intermediate multipole ranges. This anomaly is explicitly associated with the angular power spectrum, which is heavily used for cosmological model fitting. Having noted this, we have investigated whether even (odd) multipole data set is individually consistent with the WMAP concordance model. Our investigation shows that the WMAP concordance model does not make a good fit for even (odd) multipole data set, which indicates parametric tension between even and odd multipole data set. Noting that tension is highest in primordial power spectrum parameters, we have additionally considered a running spectral index, but found that tension increases to even a higher level. We believe these parametric tensions may be indications of unaccounted contamination or imperfection of the model.