Spin Correlations and Velocity-Scaling in NRQCD Matrix Elements

We compute spin-dependent matrix elements for decays of S-wave quarkonia in lattice NRQCD. They appear to be in approximate agreement with the velocity-scaling rules of NRQCD.Comment: 3 pages, uses aipproc.cls, aipxfm.sty, aip-6s.clo, Talk presented at The VIth International Conference Quark Confinement and the Hadron Spectrum, Villasimius, Sardinia, Italy September 21--25, 200

Lattice Calculation of Quarkonium Decay Matrix Elements

We calculate the NRQCD matrix elements for the decays of the lowest-lying S- and P-wave states of charmonium and bottomonium in quenched lattice QCD. We also compute the one-loop relations between the lattice and continuum matrix elements.Comment: 10 pages, LaTeX. Talk presented at the Quarkonium Physics Workshop, University of Illinois, Chicago, June 13-15, 199

Simulation of the channelling of ions from MeV C60 in crystalline solids

Simulations were performed describing the motion and breakup of energetic C60 ions interacting with crystalline targets. A hybrid algorithm was used that employs a binary collision model for the scattering of the carbon ions by the atoms of the solid, and molecular dynamics for the Coulomb interactions of the 60 carbon ions with one another. For the case of yttrium iron garnet (YIG), directions such as [1 1 0], [1 0 0], [0 1 0] and [0 0 1] demonstrate channelling for a large fraction of the C ions. For directions such as [1 1 1], [2 1 1] and [7 5 3] the trajectories show no more channelling than for random directions. The effects of tilt, shielding and wake-field interactions were investigated for YIG and α-quartz

Searching for better prospects: endogenizing falling job tenure and private pension coverage

Recent declines in job tenure have coincided with a shift away from traditional defined benefit (DB) pensions, which reward long tenure. New evidence also points to an increase in job-to-job movements by workers, and we document gains in relative wages of job-to-job movers over a similar period. We develop a search model in which firms may offer tenure-based contracts like DB pensions to reduce the incidence of costly on-the-job search by workers. Either reduced search costs or an increase in the probability of job matches can, under fairly general conditions, lower the value of deterring search and the use of DB pensions.Pensions ; Unemployment

Searching for Better Prospects: Endogenizing Falling Job Tenure and Private Pension Coverage

Recent declines in job tenure have coincided with a shift away from traditional defined benefit (DB) pensions, which reward long tenure. Recent evidence also points to an increase in job-to-job movements by workers, and we document gains in relative wages of job-to-job movers over a similar period. We develop a search model in which firms may offer tenure-based contracts like DB pensions to reduce the incidence of costly on-the-job search by workers. Reduced search costs can, under fairly general conditions, lower the value of deterring search and the use of DB pensions.

Spin correlations and velocity-scaling in color-octet NRQCD matrix elements

We compute spin-dependent decay matrix elements for S-wave charmonium and bottomonium in lattice nonrelativistic quantum chromodynamics (NRQCD). Particular emphasis is placed upon the color-octet matrix elements, since the corresponding production matrix elements are expected to appear in the dominant contributions to the production cross sections at large transverse momenta. We use three slightly different versions of the heavy-quark lattice Green's functions in order to minimize the contributions that scale as powers of the ultraviolet cutoff. The lattice matrix elements that we calculate obey the hierarchy that is suggested by the velocity-scaling rules of NRQCD.Comment: 25 pages, 2 figures, 2 tables, further discussion of effective lattice cutoffs and uncertainties, additional minor revisions, version to be published in Phys. Rev.

Ultra-dense magnetoresistive mass memory

This report details the progress and accomplishments of Nonvolatile Electronics (NVE), Inc., on the design of the wafer scale MRAM mass memory system during the fifth quarter of the project. NVE has made significant progress this quarter on the one megabit design in several different areas. A test chip, which will verify a working GMR bit with the dimensions required by the 1 Meg chip, has been designed, laid out, and is currently being processed in the NVE labs. This test chip will allow electrical specifications, tolerances, and processing issues to be finalized before construction of the actual chip, thus providing a greater assurance of success of the final 1 Meg design. A model has been developed to accurately simulate the parasitic effects of unselected sense lines. This model gives NVE the ability to perform accurate simulations of the array electronic and test different design concepts. Much of the circuit design for the 1 Meg chip has been completed and simulated and these designs are included. Progress has been made in the wafer scale design area to verify the reliable operation of the 16 K macrocell. This is currently being accomplished with the design and construction of two stand alone test systems which will perform life tests and gather data on reliabiliy and wearout mechanisms for analysis

Thermodynamics of lattice QCD with 3 flavours of colour-sextet quarks

We have been studying QCD with 2 flavours of colour-sextet quarks to distinguish whether it is QCD-like or conformal. For comparison we are now studying QCD with 3 flavours of colour-sextet quarks, which is believed to be conformal in the chiral limit. Here we present the results of simulations of lattice QCD with 3 colour-sextet quarks at finite temperatures on lattices of temporal extent $N_t=4$ and 6, with masses small enough to yield access to the chiral limit. As for the 2-flavour case, we find well-separated deconfinement and chiral-symmetry restoration transitions, both of which move to appreciably weaker couplings as $N_t$ is increased from 4 to 6. If this theory is conformal, we would expect there to be a bulk chiral transition at a fixed coupling. For this reason we conclude that for $N_t=4$ and 6, the chiral and hence the deconfinement transitions are in the strong-coupling domain where the theory is essentially quenched. The similarity between the behaviours of the 2 and 3 flavour theories suggested that the $N_t=4$ and 6 transitions for the 2-flavour theory also lie in the strong-coupling domain. The phase structure of both theories is very similar.Comment: 17 pages Latex(Revtex), 7 postscript figure

The Dunbar Water-Supply.

n/