204015985
Semileptonic decay of B and D ---> K*0 (1430) anti-l nu from QCD sum rule
We calculate B-(s) and D-(s) to K-0(*)(1430) transition form factors, and study semileptonic decays of B-(s) and D-(s)-> K-0(*)(1430)(l) over bar nu based on QCD sum rule. Measuring these semileptonic decays with high statistics will give valuable information on the nature of light scalar mesons.
45496150
Spectrum of the charmed and b-flavored mesons in the relativistic potential model
A bstractWe study the bound states of heavy-light quark-antiquark system in the relativistic potential model, where the potential includes the long-distance confinement term, the short-distance Coulomb term and spin-dependent term. The spectrum of B, B*, D, D* and states with higher orbital quantum numbers are obtained. Compared with previous results predicted in the relativistic potential model, the predictions are improved and extended in this work, more theoretical masses are predicted which can be tested in experiment in the future.
119292653
Wave functions and decay constants of B and D mesons in the relativistic potential model
With the decay constants of D and Ds mesons measured in experiment recently, we revisit the study of the bound states of quark and antiquark in B and D mesons in the relativistic potential model. The relativistic bound state wave equation is solved numerically. The masses, decay constants and wave functions of B and D mesons are obtained. Both the masses and decay constants obtained here can be seen as consistent with the experimental data. The wave functions can be used in the study of B and D meson decays.
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.
119017430
B ---> PV decays in QCD improved factorization approach
Motivated by recent CELO measurements and the progress of the theory of B decays, we investigate $B\to P V(P=\pi,K. V= K^{*},\rho,\omega)$ decay modes in the framework of QCD improved factorization. We find that all the measured branching ratios are well accommodated in the reasonable parameter space and predictions for the other decay modes are well below the experimental upper limits. We also have calculated CP asymmetries in these decay modes.
119388505
Sudakov effects in BBNS approach
The end-point singularity is an unsolved problem in BBNS approach, Incorporating the partonic transverse momentum and the Sudakov form factor, this problem can be solved model-independently. We discuss the Sudakov effects in BBNS approach. The BBNS approach is compared with the modified PQCD approach. The main idea of Sudakov form factor is briefly discussed. Our conclusion is that the twist-3 contribution for the hard spectator scattering is numerically not important in B --> pi pi decays, compared with the twist-2 contribution. (C) 2001 Published by Elsevier Science B.V.
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.
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.
27697160
350 μm Observations of Ultraluminous Infrared Galaxies at Intermediate Redshifts
We present 350 μm observations of 36 ultraluminous infrared galaxies (ULIRGs) at intermediate redshifts (0.089 ≤ z ≤ 0.926) using the Submillimeter High Angular Resolution Camera II (SHARC-II) on the Caltech Submillimeter Observatory (CSO). In total, 28 sources are detected at S/N ≥ 3, providing the first flux measurements longward of 100 μm for a statistically significant sample of ULIRGs in the redshift range 0.1 ≲ z ≲ 1.0. Combining our 350 μm flux measurements with the existing IRAS 60 and 100 μm data, we fit a single-temperature model to the spectral energy distribution (SED) and thereby estimate dust temperatures and far-IR luminosities. Assuming an emissivity index of β = 1.5, we find a median dust temperature and far-IR luminosity of T_d = 42.8 ± 7.1 K and log(L_(FIR)/L_☉) = 12.2 ± 0.5, respectively. The far-IR-radio correlation observed in local star-forming galaxies is found to hold for ULIRGs in the redshift range 0.1 ≲ z ≲ 0.5, suggesting that the dust in these sources is predominantly heated by starbursts. We compare the far-IR luminosities and dust temperatures derived for dusty galaxy samples at low and high redshifts with our sample of ULIRGs at intermediate redshift. A general L_(FIR)-T_d relation is observed, albeit with significant scatter due to differing selection effects and variations in dust mass and grain properties. The relatively high dust temperatures observed for our sample compared to that of high-z submillimeter-selected starbursts with similar far-IR luminosities suggest that the dominant star formation in ULIRGs at moderate redshifts takes place on smaller spatial scales than is found at higher redshifts.
119474898
The topological branching fractions of $\tau$ decay at LEP
The paper has heen withdrawn.
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.