118537463
Red Supergiant Stars in the Large Magellanic Cloud. I. The Period?Luminosity Relation
From previous samples of red supergiants (RSGs) by various groups, 191 objects are assembled to compose a large sample of RSG candidates in LMC. For 189 of them, the identity as an RSG is verified by their brightness and color indexes in several near- and mid-infrared bands related to the Two Micron All Sky Survey (2MASS) JHK S bands and the Spitzer/IRAC and Spitzer/MIPS bands. From the visual time-series photometric observations by the ASAS and MACHO projects which cover nearly 8-10 years, the period and amplitude of light variation are analyzed carefully using both the phase dispersion minimization and Period04 methods. According to the properties of light variation, these objects are classified into five categories: (1) 20 objects are saturated in photometry or located in crowded stellar field with poor photometric results, (2) 35 objects with too complex variation to have any certain period, (3) 23 objects with irregular variation, (4) 16 objects with semi-regular variation, and (5) 95 objects with long secondary period (LSP) among which 31 have distinguishable short period and 51 have a long period shorter than 3000 days that can be determined with reasonable accuracy. For the semi-regular variables and the LSP variables with distinguishable short periods, the period-luminosity (P-L) relation is analyzed in the visual, near-infrared, and mid-infrared bands. It is found that the P-L relation is tight in the infrared bands such as the 2MASS JHK S bands and the Spitzer/IRAC bands, in particular in the Spitzer/IRAC [3.6] and [4.5] bands; meanwhile, the P-L relation is relatively sparse in the V band which may be caused by inhomogeneous interstellar extinction. The results are compared with others' P-L relationships for RSGs and the P-L sequences of red giants in LMC.
119119152
Analysis of a selected sample of RR Lyrae stars in the LMC from OGLE-III
A systematic study of RR Lyrae stars is performed using a selected sample of 655 objects in the Large Magellanic Cloud (LMC) with long-term observations and numerous measurements from the Optical Gravitational Lensing Experiment III project. The phase dispersion method and linear superposition of the harmonic oscillations are used to derive the pulsation frequency and properties of light variation. It is found that a dichotomy exists in Oosterhoff Type I and Oosterhoff Type II for RR Lyrae stars in the LMC. Due to our strict criteria for identifying a frequency, a lower limit for the incidence rate of Blazhko modulation in the LMC is estimated in various subclasses of RR Lyrae stars. For fundamental-mode RR Lyrae stars, the rate of 7.5% is smaller than the previous result. In the case of the first-overtone RR Lyrae variables, the rate of 9.1% is relatively high. In addition to the Blazhko variables, 15 objects are identified to pulsate in the fundamental/first-overtone double mode. Furthermore, four objects show a period ratio around 0.6, which makes them very likely to be rare pulsators in the fundamental/second-overtone double mode.
14082825
350 μm Observations of Local Luminous Infrared Galaxies and the Temperature Dependence of the Emissivity Index
We report 350 μm observations of 18 nearby luminous infrared galaxies (LIRGs) using the Submillimeter High Angular Resolution Camera II (SHARC-II) mounted on the Caltech Submillimeter Observatory (CSO) 10.4 m telescope. Combining our 350 μm flux measurements with the existing far-infrared (FIR) and submillimeter data, we fit a single-temperature model to the spectral energy distributions (SEDs) and find the dust temperatures, emissivity indices, and FIR luminosities having sample medians of T_d = 39.4 ± 7.9 K, β = 1.6 ± 0.3, and LFIR = 10^(11.2±0.6) L⊙. An empirical inverse T_d-β correlation, best described by T_d = (9.86 × 10^9)^(1/(4.63 + β)), is established for the local LIRG sample, which we argue can be explained by the intrinsic interdependence between the dust temperature and grain emissivity index as physical parameters, as well as variations in grain properties in the interstellar medium (ISM).
119302071
Automatic Calibration Method of Voxel Size for Cone-beam 3D-CT Scanning System
For cone-beam three-dimensional computed tomography (3D-CT) scanning system, voxel size is an important indicator to guarantee the accuracy of data analysis and feature measurement based on 3D-CT images. Meanwhile, the voxel size changes with the movement of the rotary table along X-ray direction. In order to realize the automatic calibration of the voxel size, a new easily-implemented method is proposed. According to this method, several projections of a spherical phantom are captured at different imaging positions and the corresponding voxel size values are calculated by non-linear least square fitting. Through these interpolation values, a linear equation is obtained, which reflects the relationship between the rotary table displacement distance from its nominal zero position and the voxel size. Finally, the linear equation is imported into the calibration module of the 3D-CT scanning system, and when the rotary table is moving along X-ray direction, the accurate value of the voxel size is dynamically exported. The experimental results prove that this method meets the requirements of the actual CT scanning system, and has virtues of easy implementation and high accuracy
119474898
The topological branching fractions of $\tau$ decay at LEP
The paper has heen withdrawn.
122191513
Unconventional Geometric Quantum Gate in Circuit QED
We propose a scheme to implement an unconventional geometric phase gate in circuit QED, i.e. two superconducting charge qubits inside a superconducting transmission line resonator. The quantum operation depends only on global geometric features, and thus is insensitive to the state of the cavity mode.
204211636
Rare Semileptonic Decays of Heavy Mesons in the Heavy Quark Limit
119117884
Proceedings of the 2nd Workshop on Flavor Symmetries and Consequences in Accelerators and Cosmology (FLASY12)
Although existing theoretical models generally prefer extremely heavy right-handed neutrinos to generate light neutrino masses via the seesaw mechanism, there are several observed phenomena that point to the existence of both keVand eV-scale sterile neutrinos. We present two A4 flavor symmetry models that can accommodate light sterile neutrinos and remain compatible with neutrino data. Higher order seesaw terms and higher-dimensional operators are studied, and the phenomenological implications of light sterile neutrinos on neutrinoless double beta decay are discussed. 1.
17444064
Mass and decay constant of I=1/2 scalar meson in QCD sum rule
We calculate the mass and decay constant of I = 1/2 scalar mesons composed of quark-antiquark pairs based on QCD sum rule. The quark-antiquark pairs can be sq or qs (q = u, d) in quark model, the quantum numbers of spin and orbital angular momentum are S = 1, L = 1. We obtain the mass of the ground sate in this channel is 1.410 +/- 0.049 GeV. This result favors that K-0(*)(1430) is the lowest scalar state of sq or qs. We also predict the first excited scalar resonance of sq is larger than 2.0 GeV. (c) 2005 Elsevier B.V. All rights reserved.
118805500
Study on the mixing among the $0^{++}$ mesons around $1\sim 2$ $\mathrm{GeV}$ with the QCD sum rules
We calculate the correlation functions of $0^{++}$ $q\bar q$, $s\bar s$ and glueball in the QCD sum rules and obtain the mass matrix where non-diagonal terms are determined by the cross correlations among the three states. Diagonalizing the mass matrix and identifying the eigenstates as the physical $0^{++}$ scalar mesons, we can determine the mixing. Concretely, our calculations determine the fractions of $q\bar q$, $s\bar s$ and glueball in the physical states $f_0(1370)$, $f_0(1500)$ and $f_0(1710)$, the results are consistent with that gained by the phenomenological research.
119203345
RADIATIVE LEPTONIC DECAYS OF THE CHARGED B AND D MESONS INCLUDING LONG-DISTANCE CONTRIBUTION
In this work, we study the radiative leptonic decays of B-, D- and $D_s^-\to \gamma l \bar{\nu}$, including both the short-distance and long-distance contributions. The short-distance contribution is calculated by using the relativistic quark model, where the bound state wave function we used is that obtained in the relativistic potential model. The long-distance contribution is estimated by using vector meson dominance model.