166025
Ultralow Phase Noise Microwave Generation From Mode-Locked Er-Fiber Lasers With Subfemtosecond Integrated Timing Jitter
We demonstrate ultralow phase noise 10-GHz microwave signal generation from a free-running mode-locked Er-fiber laser with -142- and -157-dBc/Hz single-sideband absolute phase noise at 10- and 100-kHz offset frequencies, respectively. The absolute RMS timing jitter is 1.5 fs when integrated from 1-kHz to 5-GHz (Nyquist frequency) offset frequency. In the 10-kHz to 10-MHz integration bandwidth typically used for microwave generators, the RMS integrated jitter is 0.49 fs. The Er-fiber laser is operated in the stretched-pulse regime at close-to-zero dispersion to minimize the phase noise of extracted microwaves. In order to suppress the excess phase noise in the optical-to-electronic conversion process, we synchronize a low-noise voltage-controlled oscillator to the fiber laser using a fiber Sagnac-loop-based optical-microwave phase detector.
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.
119074604
Removing the ISW-lensing bias from the local-form primordial non-Gaussianity estimation
The Integrated Sachs-Wolfe (ISW) effect produces a secondary temperature aniso\-tropy of the cosmic microwave background (CMB), as CMB photons travel through time-varying potentials along the line-of-sight. The main contribution comes from redshifts z2, where dark energy leads to a decay of potentials. As the same photons are gravitationally lensed by these decaying potentials, there exists a high degree of correlation between the ISW effect and CMB lensing, leading to a non-zero three-point correlation (bispectrum) of the observed temperature anisotropy. This ISW-lensing bispectrum, whose shape resembles that of the so-called ``local-form'' primordial bispectrum parametrized by fNL, is known to be the largest contamination of fNL. In order to avoid a spurious detection of primordial non-Gaussianity, we need to remove the ISW-lensing bias. In this work, we investigate three debiasing methods: (I) subtraction of an expected, ensemble average of the ISW-lensing bispectrum; (II) subtraction of a measured ISW-lensing bispectrum; and (III) direct subtraction of an estimated ISW signal from an observed temperature map. One may use an estimation of the ISW map from external non-CMB data or that from the CMB data themselves. As the methods II and III are based on fewer assumptions about the nature of dark energy, they are preferred over the method I. While the methods I and II yield unbiased estimates of fNL with comparable error bars, the method III yields a biased result when the underlying primordial fNL is non-zero and the ISW map is estimated from a lensing potential reconstructed from the observed temperature map. One of the sources of the bias is a lensing reconstruction noise bias which is independent of fNL and can be calculated precisely, but other fNL-dependent terms are difficult to compute reliably. We thus conclude that the method II is the best, model-independent way to remove the ISW-lensing bias of fNL, enabling us to test the physics of inflation with smaller systematic errors.
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.
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.
118997460
Alfv\'en turbulence in the WMAP 5 year data and a forecast for the PLANCK
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.
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.
1814793
More on R-parity and lepton family number violating couplings from muon(ium) conversion, and tau and pi0 decays
We present a new class of constraints to the lepton-family-number- and R-parity-violating couplings from muonium conversion {mu}{sup {minus}}+{sub 22}{sup 48}Ti{r_arrow}e{sup {minus}}+{sub 22}{sup 48}Ti, a class of {tau} decays {tau}{r_arrow}l+ (light meson) with l={mu}ore, and J/{psi} and {pi}{sup 0} decays into a lepton pair. We find that {mu}{sup {minus}}+{sub 22}{sup 48}Ti{r_arrow}e{sup {minus}}+{sub 22}{sup 48}Ti provides one of the strongest constraints along with {Delta}m{sub K},{Delta}m{sub B}, {mu}{r_arrow}e{gamma}, and the neutrinoless double {beta} decay. The search for these lepton-family-number-violating decays forbidden in the standard model is clearly warranted in various low-energy experiments such as {tau}-charm factories and PSI, etc. {copyright} {ital 1997} {ital The American Physical Society}
118440632
Instantons on the 5-sphere and M5-branes
We calculate the partition functions of supersymmetric gauge theories on S^5, which acquire non-perturbative contributions from instanton loops wrapping its Hopf fiber. The instantons on the CP^2 base equivariantly localize to 3 fixed points of SU(3) Cartans. Using our results, we study the index of the 6d (2,0) theory. We first study the partition functions of maximal SYM with AD(E) gauge groups, which agree with the gravity dual indices on AdS_7 in the large N limits. We also show that the most general partition function of the Abelian theory agrees with the index for a free 6d tensor supermultiplet. We explain possible ambiguities in our 5d approach, role of maximal SUSY, and the Wilson loops on S^5 dual to M2-brane Wilson surfaces in AdS_7.
122221375
Effects of the transition magnetic moment of the neutrino
It is shown that a sizable transition magnetic moment between ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ and a massive neutrino ${\ensuremath{\nu}}^{\ensuremath{'}}$ (of mass of approximately 100 MeV) leads to some detectable effects. These effects could be revealed significantly in ${\ensuremath{\nu}}_{{\ensuremath{\mu}}^{\ensuremath{-}}} ({\overline{\ensuremath{\nu}}}_{{\ensuremath{\mu}}^{\ensuremath{-}}})$ electron scattering, but would remain hidden in most other cases. It is also pointed out under what circumstances a large transition magnetic moment arises in gauge models.