arXiv subjects

A. McKerrell

Publications and source records attributed to A. McKerrell.

5 recordsLinked to original sources

arXiv1994

Fitting Correlated Hadron Mass Spectrum Data

We discuss fitting hadronic Green functions versus time $t$ to extract mass values in quenched lattice QCD. These data are themselves strongly correlated in $t$. With only a limited number of data samples, the method of minimising correlated $χ^2$ is unreliable. We explore several methods of modelling the correlations among the data set by a few parameters which then give a stable and sensible fit even if the data sample is small. In particular these models give a reliable estimate of the goodness of fit.

hep-lat↗

arXiv1994

Efficient Hadronic Operators in Lattice Gauge Theory

We study operators to create hadronic states made of light quarks in quenched lattice gauge theory. We construct non-local gauge-invariant operators which provide information about the spatial extent of the ground state and excited states. The efficiency of the operators is shown by looking at the wave function of the first excited state, which has a node as a function of the spatial extent of the operator. This allows one to obtain an uncontaminated ground state for hadrons.

hep-lat↗

arXiv1994

Point-to-point Hadron Correlation Functions using the Sheikholeslami--Wohlert Action

We calculate correlations between hadronic current operators as a function of their spatial separation, in a quenched lattice QCD simulation at $β=6.2$ on a $24^3\times48$ lattice. The lattice fermion formulation used is that due to Sheikholeslami and Wohlert. The correlation functions are then compared with the corresponding quantities calculated in the infinite volume chiral limit of the non-interacting theory. The ratio of the two quantities contains information on the vacuum structure of QCD. Results obtained are consistent with previous studies, and with known hadron phenomenology, although certain features of the fermion action used make it impossible to probe the $r\to0$ limit directly, thus limiting the accuracy possible.

hep-lat↗

arXiv1992

SU(2) Potentials from Large Lattices

We measure accurate values of the inter-quark potentials on a $48^{3}56$ lattice with SU(2) pure gauge theory at $ β=2.85$. The scale is set by extracting the string tension - we obtain ${\sqrt K}a=0.063(3)$ at $β=2.85.$ From a careful study of the small-$R$ potentials in the region 2 GeV $< R^{-1} < 5$ GeV, we extract a running coupling constant and estimate the scale $Λ_{\msbar} = 272(24)$ MeV.

hep-lat↗

arXiv1992

Quenched Hadrons using Wilson and O(a)-Improved Fermion Actions at beta=6.2

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.

hep-lat↗