34826696
Lattice study of radiative J/ψ decay to a tensor glueball.
The radiative decay of J/ψ into a pure gauge tensor glueball is studied in the quenched lattice QCD formalism. With two anisotropic lattices, the multipole amplitudes E1(0), M2(0), and E3(0) are obtained to be 0.114(12)(6) GeV, -0.011(5)(1)  GeV, and 0.023(8)(1) GeV, respectively. The first error comes from the statistics, the Q2 interpolation, and the continuum extrapolation, while the second is due to the uncertainty of the scale parameter r0(-1)=410(20)  MeV. Thus, the partial decay width Γ(J/ψ→γG(2++)) is estimated to be 1.01(22)(10) keV, which corresponds to a large branch ratio 1.1(2)(1)×10(-2). The phenomenological implication of this result is also discussed.
118602451
QCD FACTORIZATION BASED ON SIX-QUARK OPERATOR EFFECTIVE HAMILTONIAN FROM PERTURBATIVE QCD AND CHARMLESS BOTTOM MESON DECAYS B((s)) -> pi pi, pi K, KK
The charmless bottom meson decays are systematically investigated based on an approximate six-quark operator effective Hamiltonian from perturbative QCD. It is shown that within this framework the naive QCD factorization method provides a simple way to evaluate the hadronic matrix elements of two-body mesonic decays. The singularities caused by on mass-shell quark propagator and gluon exchanging interaction are appropriately treated. Such a simple framework allows us to make theoretical predictions for the decay amplitudes with reasonable input parameters. The resulting theoretical predictions for all the branching ratios and CP asymmetries in the charmless B0, B+, Bs → ππ, πK, KK decays are found to be consistent with the current experimental data except for a few decay modes. The observed large branching ratio in B→π0π0 decay remains a puzzle though the predicted branching ratio may be significantly improved by considering the large vertex corrections in the effective Wilson coefficients. More precise measurements of charmless bottom meson decays, especially on CP violations in B → KK and Bs → ππ, πK, KK decay modes, will provide a useful test and guide us to a better understanding on perturbative and nonperturbative QCD.
54501660
Quark and Glue Momenta and Angular Momenta in the Proton --- a Lattice Calculation
We report a complete calculation of the quark and glue momenta and angular momenta in the proton. These include the quark contributions from both the connected and disconnected insertions. The calculation is carried out on a $16^3 \times 24$ quenched lattice at $\beta = 6.0$ and for Wilson fermions with $\kappa = 0.154, 0.155,$ and 0.1555 which correspond to pion masses at 650, 538, and 478 MeV. The quark loops are calculated with $Z_4$ noise and signal-to-noise is improved further with unbiased subtractions. The glue operator is comprised of gauge-field tensors constructed from the overlap operator. The $u$ and $d$ quark momentum/angular momentum fraction is 0.66(5)/0.72(5), the strange momentum/angular momentum fraction is 0.024(6)/0.023(7), and that of the glue is 0.31(6)/0.25(8). The orbital angular momenta of the quarks are obtained from subtracting the angular momentum component from its corresponding spin. As a result, the quark orbital angular momentum constitutes 0.50(2) of the proton spin, with almost all it coming from the disconnected insertion. The quark spin carries a fraction 0.25(12) and glue carries a fraction 0.25(8) of the total proton spin.
118727023
Predictive AdS/QCD Model for Mass Spectra of Mesons with Three Flavors
The predictive soft-wall AdS/QCD model with a modified 5D metric at the infrared region is constructed to obtain a nontrivial dilaton solution for three flavor quarks u, d and s. Such a model is shown to incorporate both the chiral symmetry breaking and linear confinement. After considering some high-order terms including the U(1)(L) x U(1)(R) chiral symmetry breaking term, we find that the resulting predictions for the SU(3) octet and singlet resonance states of pseudoscalar, scalar, vector and axial-vector mesons agree well with the experimentally confirmed resonance states. Contributions from the instanton effects given by the determinant term are also discussed. It is observed that the chiral symmetry breaking phenomena of SU(3)(L) x SU(3)(R) and U(1)(L) x U(1)(R) can be well described in this model, while the SU(3) flavor symmetry breaking effect due to quark mass difference in the source term is not enough to explain all of the current experimental data.
119272630
Charmless B-s -> PP, PV, VV decays based on the six-quark effective Hamiltonian with strong phase effects II
We provide a systematic study of charmless B-s -> PP, PV, VV decays (P and V denote pseudoscalar and vector mesons, respectively) based on an approximate six-quark operator effective Hamiltonian from QCD. The calculation of the relevant hard-scattering kernels is carried out, the resulting transition form factors are consistent with the results of QCD sum-rule calculations. By taking into account important classes of power corrections involving "chirally enhanced" terms and the vertex corrections as well as weak annihilation contributions with non-trivial strong phase, we present predictions for the branching ratios and CP asymmetries of B-s decays into PP, PV and VV final states, and also for the corresponding polarization observables in VV final states. It is found that the weak annihilation contributions with non-trivial strong phase have remarkable effects on the observables in the color-suppressed and penguin-dominated decay modes. In addition, we discuss the SU(3) flavor symmetry and show that the symmetry relations are generally respected.
119236514
Scalar Glueball in Radiative J/psi Decay on the Lattice
The form factors in the radiative decay of J/psi to a scalar glueball are studied within quenched lattice QCD on anisotropic lattices. The continuum extrapolation is carried out by using two different lattice spacings. With the results of these form factors, the partial width of J/psi radiatively decaying into the pure gauge scalar glueball is predicted to be 0.35(8) keV, which corresponds to a branching ratio of 3.8(9) x 10(-3). By comparing with experiments, out results indicate that f(0)(1710) has a larger overlap with the pure gauge glueball than other related scalar mesons. DOI: 10.1103/PhysRevLett.110.021601
118435494
Possible interpretation of the Zb(10610) and Zb(10650) in a chiral quark model
Motivated by the two charged bottomonium-like resonances Zb(10610) and Zb(10650) newly observed by the Belle collaboration, the possible molecular states composed of a pair of heavy mesons, , etc (in S-wave), are investigated in the framework of chiral quark models by the Gaussian expansion method. The bound states and with quantum numbers I(JPC) = 1(1+−), which are good candidates for the Zb(10610) and Zb(10650), respectively, are obtained. Another three bound states with I(JPC) = 0(1++), with I(JPC) = 1(0++), 0(2++) are predicted. These states may be observed in an open-bottom or a hidden-bottom decay channel of highly excited ϒ. When directly extending the quark model to the hidden-color channel of the multi-quark system, more deeply bound states are found. Future experimental search of those states will cast doubt on the validity of applying the chiral constituent quark model to the hidden-color channel directly.
119114673
Charmonium States in QCD-Inspired Quark Potential Model Using Gaussian Expansion Method
We investigate the mass spectrum and electromagnetic processes of charmonium system with the nonperturbative treatment for the spin-dependent potentials, comparing the pure scalar and scalar-vector mixing linear confining potentials. It is revealed that the scalar-vector mixing confinement would be important for reproducing the mass spectrum and decay widths, and therein the vector component is predicted to be around 22 %. With the state wave functions obtained via the full-potential Hamiltonian, the long-standing discrepancy in M1 radiative transitions of J/ψ and ψ′ are alleviated. This work also provides an inspection and suggestion for the possible cc̄ states among the copious higher charmonium-like states. Particularly, the newly observed X(4160) and X(4350) are found in the charmonium family mass spectrum as M(21D2) = 4164.9 MeV and M(33P2) = 4352.4 MeV, which strongly favor the JPC = 2−+, 2++ assignments respectively. The corresponding radiative transitions, leptonic and two-photon decay widths have been also predicted theoretically for the further experimental search.
1941882
Reexamining charmless B ---> PV decays in QCD factorization approach
Using the QCD factorization approach, we reexamine the two-body hadronic charmless $B$-meson decays to final states involving a pseudoscalar~($P$) and a vector~($V$) meson, with inclusion of the penguin contractions of spectator-scattering amplitudes induced by the $b\to D g^\ast g^\ast$~(where $D=d$ or $s$, and $g^\ast$ denotes an off-shell gluon) transitions, which are of order $\alpha_s^2$. Their impacts on the CP-averaged branching ratios and CP-violating asymmetries are examined. We find that these higher order penguin contraction contributions have significant impacts on some specific decay modes. Since $B\to \pi K^{\ast}$, $K \rho$ decays involve the same electro-weak physics as $B\to \pi K$ puzzles, we present a detailed analysis of these decays and find that the five R-ratios for $B\to \pi K^{\ast}$, $K \rho$ system are in agreement with experimental data except for $R(\pi K^*)$. Generally, these new contributions are found to be important for penguin-dominated $B\to PV$ decays.
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.
117973255
A New Approach to the Yang-Mills Gauge Theory of Gravity and It's Applications
We shall give dynamics to our spacetime manifold by first identifying the local affine symmetry as the characterizing symmetry for our geometryla Felix Klein, this symmetry is imposed on us by the Law of Inertia and the Law of Causality. We then prescribe 16 gauge vector bosons to this symmetry ´ ala Yang and Mills. The locally affine symmetric Yang-Mills Lagrangian in the presence of a background world metric, and the corresponding equations of motion, are respectively constructed and derived. Spontaneous breaking of the local affine symmetry to the local Lorentz symmetry is achieved by classical solutions to the equations of motion. In these classical solutions, the 16 gauge vector bosons are shown to select the Schwarzschild metric as one among the admissible background world metrics. Classical gravity is thus be expressed by a spontaneously broken Erlangen program. We shall also show that this Yang-Mills gauge theory of gravity can give an explanation of the form of the galactic rotation curves, of the amount of intergalactic gravitational lensing, and of the accelerating expansion of the Universe.