arXiv subjects
Publications and source records attributed to P. J. S. Watson.
There has been considerable interest in providing new limits on the short range behaviour of gravity, or, in general, anomalous short-range interactions. In this note we show that one use the interaction of ultra-cold neutrons to obtain a better limit below about 10 nm.
The recent observation of the quantum state of the neutron bouncing freely under gravity allows some novel experiments. A method of purifying the ground state is given, and possible applications to the measurement of the electric dipole moment of the neutron and the short distance behaviour of gravity are discussed.
It has been shown that the string-flip potential model reproduces most of the bulk properties of nuclear matter, with the exception of nuclear binding. Furthermore, it was postulated that this model with the inclusion of the colour-hyperfine interaction should produce binding. In some recent work a modified version of the string-flip potential model was developed, called the flux-bubble model, which would allow for the addition of perturbative QCD interactions. In attempts to construct a simple $q\bar q$ nucleon system using the flux-bubble model (which only included colour-Coulomb interactions) difficulties arise with trying to construct a many-body variational wave function that would take into account the locality of the flux-bubble interactions. In this paper we look at a toy system, a mesonic molecule, in order to understand these difficulties. {\it En route}, a new variational wave function is proposed that may have a sufficient impact on the old string-flip potential model results that the inclusion of perturbative effects may not be needed.
It has been shown that the string-flip potential model reproduces most of the bulk properties of nuclear matter, with the exception of nuclear binding. Furthermore, it was postulated that this model, with the inclusion of the colour-hyperfine interaction, should produce binding. In some recent work a modified version of the string-flip potential model was developed, called the flux-bubble model, which would allow for the addition of perturbative QCD interactions. In attempts to construct a simple $q\bar q$ nucleon system using the flux-bubble model (which only included colour-Coulomb interactions) difficulties arose with trying to construct a many-body variational wave function that would take into account the locality of the flux-bubble interactions. In this talk we consider a toy system, a mesonic molecule in order to understand these difficulties. En route, a new variational wave function is proposed that may have a significant enough impact on the old string-flip potential model results that the inclusion of perturbative effects may not be needed.
For over 50 years attempts have been made to explain the properties of nuclear matter in terms of constituent nucleons with very little success. Here we will investigate one class of many possible models, string-flip potential models, in which flux-tubes are connected between quarks (in a gas/plasma) to give a minimal overall field configuration. A general overview of the current status of these models, along with some of our recently finished work, shall be given. It shall be shown that these models seem promising in that they do get most of the bulk properties of nuclear matter correct with the exception of nuclear binding. Finally we will conclude with a brief discussion on ways to improve the string-flip potential models in an attempt to obtain nuclear binding (currently we are investigating short range one-gluon exchange effects -- some preliminary results shall be mentioned).
A Monte Carlo model for nuclear matter using a many body $SU_c(3)$ string flip potential, with fixed colour, is investigated. The potential is approximated by considering colour singlet flux tube formations that connect only three quarks at a time. The model is compared with a similar string flip model, proposed by Horowitz and Piekarewicz \cite{kn:HorowitzI}, that approximates higher order flux tube formations by connecting quarks in colour singlet chains. The former model gives an EMC nucleon ``swelling'' effect, whereas the latter gives an opposite effect. Possible discrepancies between the two models are discussed.