arXiv subjects
Publications and source records attributed to S. Collins.
Preliminary results from an extensive lattice calculation of the B, B_c, and Υspectrum at quenched β= 6.0 are presented. The study includes radially and orbitally excited mesons, and baryons containing b quarks. The b quarks are formulated using NRQCD; for light and c quarks, a tadpole-improved clover action is used.
We present quenched results for B meson decay constants using NRQCD b quarks and O(a) tadpole improved clover light quarks. For the first time, one-loop matching factors between lattice and continuum currents are incorporated through O(α/M) taking operator mixing fully into account. This includes an important O(αa) discretization correction to the heavy-light axial vector current. We find f_B = 0.147(11)(^{+8}_{-12})(9)(6) MeV and f_{B_s}/f_B = 1.20(4)(^{+4}_{-0}). PACS numbers: 12.38.Gc, 12.39.Hg, 13.20.He, 14.40.Nd
We present results on the spectrum of B and D mesons including radial excitations and discuss the pseudoscalar decay constant. The results are obtained at beta=5.7 in the quenched approximation using NRQCD for the heavy quark. To study scaling violations we also compare to results obtained at beta=6.0.
We present results for the exotic $0^{+-}$ and $1^{-+}$ $b\bar{b}g$ hybrids at $β=6.0$. A leading order NRQCD action is used to generate the heavy quark propagators. The optimisation of operators is discussed and we compare our results to the predictions of recent potential calculations.
We present a quenched lattice calculation of heavy-light meson decay constants, using non-relativistic (NRQCD) heavy quarks in the mass region of the $b$ quark and heavier, and clover-improved light quarks. The NRQCD Hamiltonian and the heavy-light current include the corrections at first order in the expansion in the inverse heavy quark mass. We study the dependence of the decay constants on the heavy meson mass $M$, for light quarks with the tree level ($c_{SW}$ = 1), as well as the tadpole improved clover coefficient. We compare decay constants from NRQCD with results from clover ($c_{SW}=1$) heavy quarks. Having calculated the current renormalisation constant $Z_A$ in one-loop perturbation theory, we demonstrate how the heavy mass dependence of the pseudoscalar decay constants changes after renormalisation. For the first time, we quote a result for $f_B$ from NRQCD including the full one-loop matching factors at $O(α/M)$.
We present results for the spectrum and decay constants of B mesons from NRQCD using dynamical configurations at $β=5.6$ with two flavours of staggered fermions. The light quarks are generated using the Clover action with tadpole improvement.
We present a lattice investigation of the heavy-light meson decay constants using Wilson light quarks and NRQCD heavy quarks, partially including the effects of dynamical sea quarks. We calculate the pseudoscalar and vector decay constants over a wide range in heavy quark mass and are able to perform a detailed analysis of heavy quark symmetry. We find consistency between the extrapolation of the NRQCD results and the static case, as expected. We find the slope of the decay constants with $1/M$ is significantly larger than naive expectations and the results of previous lattice calculations. For the first time we extract the non-perturbative coefficients of the slope arising from the $O(1/M)$ heavy quark interactions separately and show the kinetic energy of the heavy quark is dominant and responsible for the large slope. In addition, we find that significant systematic errors remain in the decay constant extracted around the $B$ meson mass due to truncating the NRQCD series at $O(1/M)$. We estimate the higher order contributions to $f_B$ are approximately $20\%$; roughly the same size as the systematic errors introduced by using the Wilson action for light quarks.
We present a lattice investigation, partially including the effects of dynamical quarks, of the heavy-light mesons using NRQCD for the heavy quark and the Wilson action for the light quark. We performed an extensive calculation of the spectrum employing a multi-state, multi-exponential fitting analysis which enabled us to extract the $2S{-}1S$ splitting as well as the $^1P_1{-}\bar{S}$ and hyperfine splittings. The Wilson action introduces a large systematic error into the calculation, and within this uncertainty we obtain agreement with experiment. We performed a comprehensive calculation of the heavy-light meson mass, investigating three methods and their range of validity. The agreement found between these methods confirms that Lorentz invariance can be restored at this order in NRQCD by a constant shift to all masses. We calculated spectroscopic quantities over a wide range in heavy quark mass and were able to perform a detailed investigation of heavy quark symmetry around the $b$ quark mass. In particular, we extracted the nonperturbative coefficients of terms in the heavy quark expansion of the meson binding energy. We demonstrate the importance of using tadpole-improved operators in such a calculation.
We present a lattice investigation of heavy-light mesons in the quenched approximation, using non-relativistic QCD for the heavy quark and a clover improved Wilson formulation for the light quark. A comprehensive calculation of the heavy-light spectrum has been performed for various heavy quark masses around the $b$. Our results for the $B_s-B_d$ splitting agree well with the experimental value. We find the $Λ_b-B$ splitting to be compatible with experiment, albeit with large error bars. Our $B^*-B$ splitting is slightly low, which could be explained as an effect of quenching. For the first time, we are able to estimate the mass of $P$ states at the $B$ and compare them with experiment.
We present {\it preliminary} results for the decay constants of heavy-light mesons using NRQCD heavy and tadpole improved Clover light quarks. A comparison is made with data obtained using Wilson light quarks. We present an analysis of the 1/M corrections to the decay constants in the static limit and compare with the predictions of HQET.
We present results on the spectrum of B mesons and heavy baryons, using a non-relativistic formulation for the heavy and a clover action for the light quark. We also discuss B meson decay constants and their dependency upon the heavy meson mass.
In this work we present lattice calculations of the masses of P-wave mesons using Monte Carlo simulations. Our valence fermions are defined by the Wilson action. Our gauge fields are generated with both dynamical staggered fermions at a lattice coupling $β\equiv 6/g^2=5.6$ for sea quark masses of $am_q=0.010$ and 0.025, and in the quenched approximation at $β=6.0$. We present results for charm and charmonium spectroscopy and use them to compute the strong coupling constant $α_s$. We compare our results to those of other recent lattice calculations and experiments.
Preliminary results on spectrum and decay constant of $B$ mesons from a quenched simulation at $β= 6.0$ on an $16^3\times48$ lattice are discussed. The heavy quark has been implemented using both an NRQCD and the static formulation, the light one with a clover improved Wilson formulation. Both the NRQCD Hamiltonian and the heavy-light current consistently include terms of $O(1/M_{Q})$, the inverse heavy quark mass.
We present {\it preliminary} results for the spectrum and decay constants of B mesons using NRQCD heavy and Wilson light quarks on configurations at $β=5.6$ with two dynamical flavours of staggered fermions. All terms to order $1/M_Q$ are included in the NRQCD action; matrix elements are corrected to this order by calculating the small components of the heavy quark propagator.
We describe two calculations involving P-wave mesons made of Wilson quarks: the strong coupling constant $α_s$ in the presence of two flavors of light dynamical fermions and the mass and decay constant of the $a_1$ meson.
We present the first study of the light hadron spectrum and decay constants for quenched QCD using an O(a)-improved nearest-neighbour Wilson fermion action at β=6.2. We compare the results with those obtained using the standard Wilson fermion action, on the same set of 18 gauge field configurations of a 24^3 times 48 lattice. For pseudoscalar meson masses in the range 330-800 MeV, we find no significant difference between the results for the two actions. The scales obtained from the string tension and mesonic sector are consistent, but differ from that derived from baryon masses. The ratio of the pseudoscalar decay constant to the vector meson mass is roughly independent of quark mass as observed experimentally, and in approximate agreement with the measured value.