相关论文: Hyperfine splittings in the $b\bar{b}$ system
We perform a quark model calculation of the $b\bar{b}$ and $c\bar{c}$ spectra from a screened funnel potential form suggested by unquenched lattice calculations. A connection between the lattice screening parameter and an effective gluon…
The ground-state energy of the Hubbard model on a Bethe lattice with infinite connectivity at half filling is calculated for the insulating phase. Using Kohn's transformation to derive an effective Hamiltonian for the strong-coupling limit,…
We present an evaluation of heavy quarkonium states (bottomium and charmonium) from first principles. We use tree-level QCD (including relativistic corrections) and the full one-loop potential; nonperturbative effects are taken into account…
We analyze the supersymmetric (SUSY) QCD contribution to the $h^0 b \bar{b}$ coupling at one loop in the Minimal Supersymmetric Model (MSSM) in the decoupling limit. Analytic expressions in the large SUSY mass region are derived and the…
The ground state hyperfine splitting in positronium, $\Delta _{\mathrm{HFS}}$, is sensitive to high order corrections of QED. A new calculation up to $O(\alpha ^3)$ has revealed a $3.9 \sigma$ discrepancy between the QED prediction and the…
Heavy-light bound states are studied in Lattice QCD with emphasis on parameters of the B-system relevant to experiment. Results are obtained on lattices with lattice spacings from about 0.15 fm to 0.06 fm corresponding to $\beta=5.74, 6.0$…
The spectrum of the Upsilon system is investigated using the Nonrelativistic Lattice QCD approach to heavy quarks and ignoring light quark vacuum polarization. We find good agreement with experiment for the Upsilon(1S), Upsilon(2S),…
We present a short review of our most recent high statistics lattice determinations in the HQET of the following important parameters in B physics: the B--meson binding energy, $\overline{\Lambda}$ and the kinetic energy of the b quark in…
The one-loop self-energy correction to the hyperfine splitting of the 1s and 2s levels in H-like low-Z atoms is evaluated to all orders in Z\alpha. The results are compared to perturbative calculations. The residual higher-order…
We propose a method for a QCD based calculation of one-particle inclusive decays of the form B \to \bar D X or B \to \bar D^* X. It is based on the heavy mass limit and a short distance expansion of the amplitudes, which yield a power…
The $\Sigma_c^*-\Sigma_c$ and $\Sigma_b^*-\Sigma_b$ hyperfine mass splittings are computed in the Skyrme model. The hyperfine splittings are suppressed by both $1/N_c$ and by $1/m_Q$, where $N_c$ is the number of colors and $m_Q$ is the…
Electronic states on the Bi/InAs(110)-(2$\times$1) surface and its spin-polarized structure are revealed by angle-resolved photoelectron spectroscopy (ARPES), spin-resolved ARPES, and density-functional-theory calculation. The surface state…
We give results for the $B$ and the $D$ meson spectrum using NRQCD on the lattice in the quenched approximation. The masses of radially and orbitally excited states are calculated as well as $S$-wave hyperfine and $P$-wave fine structure.…
Very recently, the two-photon decay width of the $\eta_b$ meson was computed with lattice QCD methods. This decay has not yet been measured. The knowledge of this width allows for the calculation of the $\eta_b$ production cross section…
We examine the spectra and radiative decays of the cc-bar and bb-bar systems using a model which incorporates the complete one-loop spin-dependent perturbative QCD short distance potential, a linear confining term including (spin-dependent)…
The bottomonium spectrum is computed in dynamical 2+1 flavor lattice QCD, using NRQCD for the b quarks. The main calculations in this work are based on gauge field ensembles generated by the RBC and UKQCD collaborations with the Iwasaki…
The hyperfine structure splittings of the ground states of the $pd\mu, pt\mu$ and $dt\mu$ ions are determined with the use of highly accurate expectation values of the interparticle delta-functions obtained in recent computations. The…
QCD string model formulated in the framework of the Field Correlator Method (FCM) in QCD is employed to calculate the masses of $\Sigma_c$, $\Xi_c$ and recently observed at Tevatron $\Sigma_b$, $\Xi_b$ baryons and their orbital excitations.…
We present a new expansion scheme to compute the rate for parton splittings in dense and finite QCD media. In contrast to the standard opacity expansion, our expansion is performed around the harmonic oscillator whose characteristic…
Positronium is an ideal system for the research of QED in the bound state. The hyperfine splitting of positronium (Ps-HFS: about 203 GHz) is a good tool to test QED and also sensitive to new physics beyond the Standard Model. Previous…