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W. Dimm

Publications and source records attributed to W. Dimm.

4 recordsLinked to original sources
arXiv1995

Lattice QCD on Small Computers

We demonstrate that lattice QCD calculations can be made $10^3$--$10^6$ times faster by using very coarse lattices. To obtain accurate results, we replace the standard lattice actions by perturbatively-improved actions with tadpole-improved correction terms that remove the leading errors due to the lattice. To illustrate the power of this approach, we calculate the static-quark potential, and the charmonium spectrum and wavefunctions using a desktop computer. We obtain accurate results that are independent of the lattice spacing and agree well with experiment.

hep-lat↗
arXiv1994

QCD on Coarse Lattices

We show that the perturbatively-improved gluon action for QCD, once it is tadpole-improved, gives accurate results even with lattice spacings as large as 0.4~fm. {\em No\/} tuning of the couplings is required. Using this action and lattice spacing, we obtain a static potential that is rotationally invariant to within a few percent, the spin-averaged charmonium spectrum accurate to within 30--40~MeV, and scaling to within 5--10\%. We demonstrate that simulations on coarse lattices are several orders of magnitude less costly than simulations using current methods.

hep-lat↗
arXiv1993

Heavy Quark and Chiral Symmetry Predictions for Semileptonic Decays B->D(D*),pi,l,nu

We study in detail the prediction for the semileptonic decays $\bar{B} \to D (D^*) π\ell \barν$ by heavy quark and chiral symmetry. The branching ratio for $\bar{B} \to D π\ell \barν$ is quite significant, as big as $(0.5-1)\%$. The branching ratio for $\bar{B} \to D^* π\ell \barν$ is only of order $10^{-4}-10^{-5}$. Numerical results for various single particle spectra and their dependence on the pion momentum cutoff schemes are presented in a series of figures, as are the model independent ratios for differential rates of $D$ and $D^*$. We also study the parity-violation effects on the decay rates for different polarization states of the $D^*$. Figures may be obtained by anonymous FTP from strange.tn.cornell.edu in the directory pub/CLNS931204, or by email from the author.

hep-ph↗