6862555
Subfemtosecond synchronization of microwave oscillators with mode-locked Er-fiber lasers.
We synchronize an 8.06 GHz microwave signal from a voltage-controlled oscillator with an optical pulse train from a 77.5 MHz mode-locked Er-fiber laser using a fiber-based optical-microwave phase detector. The residual phase noise between the optical pulse train and the synchronized microwave signal is -133 dBc/Hz (-154 dBc/Hz) at 1 Hz (5 kHz) offset frequency, which results in 838 as integrated rms timing jitter [1 Hz-1 MHz]. The long-term residual phase drift is 847 as (rms) measured over 2 h, which reaches 4×10(-19) fractional frequency instability at 1800 s averaging time. This method has a potential to provide both subfemtosecond-level short-term phase noise and long-term phase stability in microwave extraction from mode-locked fiber lasers.
118997460
Alfv\'en turbulence in the WMAP 5 year data and a forecast for the PLANCK
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.
118530966
How accurately can we measure the hydrogen 2S->1S transition rate from the cosmological data?
Recent progress in observational cosmology, and especially the forthcoming PLANCK mission data, open new directions in so-called precision cosmology. In this paper we illustrate this statement considering the accuracy of cosmological determination of the two-quanta decay rate of 2s hydrogen atom state. We show that the PLANCK data will allow us to measure this decay rate significantly better than in the laboratory experiments.
17325286
THE GAUSS–LEGENDRE SKY PIXELIZATION FOR THE CMB POLARIZATION (GLESP-POL) ERRORS DUE TO PIXELIZATION OF THE CMB SKY
We present the development of the method for numerical analysis of polarization in the Gauss–Legendre sky pixelization (GLESP) scheme for CMB maps. This incorporation of the polarization transforms in the pixelization scheme GLESP completes the creation of our new method for numerical analysis of CMB maps. A comparison of GLESP and HEALPix calculations is done.
118455901
CMB data constraint on self-annihilation of dark matter particles
Recently, self‐annihilation of dark matter particles is proposed to explain the “WMAP Haze” and excess of energetic positrons and electrons in ATIC and PAMELA results. If self‐annihilation of dark matter occurs around the recombination of cosmic plasma, energy release from self‐annihilation of dark matter delays the recombination, and hence affects CMB anisotropy. By using the recent CMB data, we have investigated the self‐annihilation of dark matter particles. In this investigation, we do not find statistically significant evidence, and impose an upper bound on 〈σν〉/mϰ.The upcoming data from Planck surveyor and the Fermi Gamma‐ray telescope will allow us to break some of parameter degeneracy and improve constraints on self‐annihilation of dark matter particles.
121983327
Natural embedding of Peccei-Quinn symmetry in flavor grand unification
Peccei and Quinn's global U(1)/sub A/ symmetry can be embedded in grand unified schemes without an artificial requirement of imposing U(1)/sub A/ symmetry, which results from the representation content of fermions and Higgs fields. Then, in some cases there results an ordinary axion with a mass approx.100 keV. The axion mass is proportional to v/sub A/ /sup -1/, where v/sub A/ /sup -1/ is the scale of the actual U(1)/sub A/-symmetry breakdown.
17690217
Exact cosmological solution and modulus stabilization in the Randall-Sundrum model with bulk matter
Abstract We provide the exact time-dependent cosmological solutions in the Randall-Sundrum (RS) setup with bulk matter, which may be smoothly connected to the static RS metric. In the static limit of the extra dimension, the solutions are reduced to the standard Friedmann equations. In view of our solutions, we also propose an explanation for how the extra dimension is stabilized in spite of a flat modulus potential at the classical level.
118390901
The CKM matrix with maximal CP violation from Z 12 symmetry
Abstract The recent accurate determination of the CKM parameters including the maximal CP phase π 2 enables us to write down the up-type and down-type quark mass matrices to a high degree of accuracy. The lightest element ( u ¯ u element) of the quark mass texture (not the mass eigenvalue) has a power λ 6 where λ = sin θ C . The CP phase of 2 π divided by an integer hints a discrete symmetry. Since λ 6 is the highest power of λ among the quark mass matrix elements, we present as an example a possibility that the maximal CP phase π 2 is obtainable from a supersymmetric Z 12 discrete symmetry model.
14469939
Z12−I Orbifold Compactification toward SUSY Standard Model
We explain the orbifold compactification in string models and present a Z12−I orbifold compactification toward supersymmetric standard models. We also point out an effective R-parity from this string construction. The VEVs of gauge singlets are chosen such that phenomenological constraints are satisfied.
118141211
Parametrization of the CKM matrix
Noting the hierarchy between three mixing angles, $\theta_{2,3}={\cal O}(\theta_1^2)$, we present an exact form of the quark mixing matrix, replacing Wolfenstein's approximate form. In addition, we suggest to rotate the unitarity triangle, using the weak CP phase convention where the phase is located at the (31) element $\sin\theta_1\sin\theta_2 e^{i\delta}$ while the (13) element $\sin\theta_1\sin\theta_3$ is real. For the $(ab)$ unitarity triangle, the base line (x-axis) is defined from the product of the first row elements, $V_{1a}V^*_{1b}$, and the angle between two sides at the origin is defined to be the phase $\delta$. This is a useful definition since every Jarlskog triangle has the angle $\delta$ at the origin, defined directly from the unitarity condition. It is argued that $\delta$ represents the barometer of the weak CP violation, which can be used to relate it to possible Yukawa textures.