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.
119288185
Radiative and leptonic decays of the pseudoscalar charmonium state eta(c)
The radiative and leptonic decays of {eta}{sub c}{yields}{gamma}{gamma} and {eta}{sub c}{yields}l{sup +}l{sup -} are studied. For a {eta}{sub c}{yields}{gamma}{gamma} decay, the second-order electromagnetic tree-level diagram gives the leading contribution. The decay rate of {eta}{sub c}{yields}{gamma}{gamma} is calculated, the prediction is in good agreement with the experimental data. For {eta}{sub c}{yields}l{sup +}l{sup -}, both the tree and loop diagrams are calculated. The analysis shows that the loop contribution dominates; the contribution of tree diagram with a Z{sup 0} intermediate state can only modify the decay rate by less than 1%. The prediction of the branching ratios of {eta}{sub c}{yields}e{sup +}e{sup -} and {mu}{sup +}{mu}{sup -} are very tiny within the standard model. The smallness of these predictions within the standard model makes the leptonic decays of {eta}{sub c} sensitive to physics beyond the standard model. Measurement of the leptonic decay may give information about new physics.
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.
118395218
Rare semileptonic decays of heavy mesons with flavor SU(3) symmetry
AbstractIn this paper, we calculate the decay rates of the D+→D0e+ν, DS+→D0e+ν, 
$B^{0}_{S}\rightarrow B^{+}e^{-}\overline{\nu}$
, DS+→D+e−e+ and BS0→B0e−e+ semileptonic decay processes, in which only the light quarks decay, while the heavy flavors remain unchanged. The branching ratios of these decay processes are calculated with the flavor SU(3) symmetry. The uncertainties are estimated by considering the SU(3) breaking effect. We find that the decay rates are very tiny in the framework of the standard model. We also estimate the sensitivities of the measurements of these rare decays at future experiments, such as BES-III, super-B and LHC-b.
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.
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.
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.
119474898
The topological branching fractions of $\tau$ decay at LEP
The paper has heen withdrawn.
21618508
Dirac versus Weyl fermions in topological insulators: Adler-Bell-Jackiw anomaly in transport phenomena.
Dirac metals (gapless semiconductors) are believed to turn into Weyl metals when perturbations, which break either time reversal symmetry or inversion symmetry, are employed. However, no experimental evidence has been reported for the existence of Weyl fermions in three dimensions. Applying magnetic fields near the topological phase transition from a topological insulator to a band insulator in Bi1-xSbx we observe not only the weak antilocalization phenomenon in magnetoconductivity near zero magnetic fields (B<0.4  T), but also its upturn above 0.4 T only for E//B. This "incompatible" coexistence between weak antilocalization and "negative" magnetoresistivity is attributed to the Adler-Bell-Jackiw anomaly ("topological" E·B term) in the presence of weak antilocalization corrections.
118829814
QCD corrections to neutron electric dipole moment from dimension-six four-quark operators
Abstract In this Letter, the renormalization-group equations for the (flavor-conserving) CP-violating interaction are derived up to the dimension six, including all the four-quark operators, at one-loop level. We apply them to the models with the neutral scalar boson or the color-octet scalar boson which have CP-violating Yukawa interactions with quarks, and discuss the neutron electric dipole moment in these models.
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.