15197087
Bounds and implications of neutrino magnetic moments from atmospheric neutrino data
The neutral current effects of the future high statistics atmospheric neutrino data can be used to distinguish the mechanisms between a ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ oscillation to a tau neutrino or to a sterile neutrino. However, if neutrinos possess large diagonal and/or transition magnetic moments, the neutrino magnetic moments can contribute to the neutral current effects which can be studied by the single ${\ensuremath{\pi}}^{0}$ production events in the Super-K data. This effect should be included in the future analyses of atmospheric data in the determination of ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ to tau or sterile neutrino oscillation.
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.
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.
118753210
CP asymmetries in the supersymmetric trilepton signal at the LHC
In the CP-violating Minimal Supersymmetric Standard Model, we study the production of a neutralino–chargino pair at the LHC. For their decays into three leptons, we analyze CP asymmetries which are sensitive to the CP phases of the neutralino and chargino sector. We present analytical formulas for the entire production and decay process, and identify the CP-violating contributions in the spin correlation terms. This allows us to define the optimal CP asymmetries. We present a detailed numerical analysis of the cross sections, branching ratios, and the CP observables. For light neutralinos, charginos, and squarks, the asymmetries can reach several 10%. We estimate the discovery potential for the LHC to observe CP violation in the trilepton channel.
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.
16726847
Testing neutrino masses in the R-parity violating minimal supersymmetric standard model with LHC results
Within the R–parity violating minimal supersymmetric standard model (MSSM), we use a hierarchical ansatz for the lepton–number violating trilinear Yukawa couplings by relating them to the corresponding Higgs–Yukawa couplings. This ansatz reduces the number of free parameters in the lepton–number violating sector from 36 to 6. Baryon–number violating terms are forbidden by imposing the discrete gauge symmetry Baryon Triality. We fit the lepton–number violating parameters to the most recent neutrino oscillation data, including the mixing angle θ13 found by Daya Bay. We find that we obtain phenomenologically viable neutrino masses and mixings only in the case of normal ordered neutrino masses and that the lepton–number violating sector is unambiguously determined by neutrino oscillation data. We discuss the resulting collider signals for the case of a neutralino as well as a scalar tau lightest supersymmetric particle. We use the ATLAS searches for multi–jet events and large transverse missing momentum in the 0, 1 and 2 lepton channel with 7 TeV center–of–mass energy in order to derive exclusion limits on the parameter space of this R–parity violating supersymmetric model.
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.
119291744
Neutrino masses and mixings in the baryon triality constrained minimal supersymmetric standard model
We discuss how the experimental neutrino oscillation data can be realized in the framework of the baryon triality ($B_3$) constrained supersymmetric Standard Model (cSSM). We show how to obtain phenomenologically viable solutions, which are compatible with the recent WMAP observations. We present results for the hierarchical, inverted and degenerate cases which illustrate the possible size and structure of the lepton number violating couplings. We work with a new, as yet unpublished version of SOFTSUSY, where we implemented full one--loop neutrino masses. Finally, we shortly discuss some phenomenological implications at the LHC.