Point Charge Dynamics Near a Grounded Conducting Plane

The classic image problem in electromagnetism involves a grounded infinite conducting plane and a point charge. The force of attraction between the point charge and the plane is identified using an equivalent-field picture of an image charge with opposite sign equidistant behind the plane resulting in a 1/{\it r}$^{\rm 2}$ force of attraction between the original charge and the plane. If the point charge is released from rest it will reach the plane in a time $\tau$. This time $\tau$ has not been calculated correctly up to now. Clarification of the inconsistency is presented along with a correct solution to the classic image problem. Other electromagnetism problems are mentioned with attractive 1/{\it r}$^{\it n}$ forces (where {\it n} $\ge$ 1). Such situations arise between a point charge and a line charge (1/{\it r}), between a line charge and a point dipole (1/{\it r}$^{2}$), between a point charge and a point dipole (1/{\it r}$^{3})$, and between a point dipole and a second point dipole (1/{\it r}$^{4}$).Comment: 6 pages, 4 figure

Phi Meson Propagation and Decay at Finite Temperature

We study spectral properties of the phi meson at finite temperature using an effective Lagrangian together with finite-temperature field theory as a basis for modeling. General field-theoretic arguments are then used to establish the lifetime of the phi in hot hadronic matter. We find from the model, and we therefore propose a scenario in which, the phi decays inside the fireball. Early decays into $\mu^{+}\mu^{-}$ occur at high temperature while measurable hadronic decays into $K^{+}K^{-}$ (not suffering rescattering) occur at freezeout, where flow could be substantial. These results provide a consistent picture, if not possible interpretation of the NA49 and NA50 data from CERN.Comment: 7 pages, 3 postscript figures, Talk given at the 20th Winter Workshop on Nuclear Dynamics, Trelawny Beach, Jamaica, 15-20 March 200

Dilepton Production in Nucleon-Nucleon Reactions With and Without Hadronic Inelasticities

We calculate elementary proton-proton and neutron-proton bremsstrahlung and their contribution to the $e^+e^-$ invariant mass distribution. At 4.9 GeV, the proton-proton contribution is larger than neutron-proton, but it is small compared to recent data. We then make a first calculation of bremsstrahlung in nucleon-nucleon reactions with multi-hadron final states. Again at 4.9 GeV, the many-body bremsstrahlung is larger than simple nucleon-nucleon bremsstrahlung by more than an order of magnitude in the low-mass region. When the bremsstrahlung contributions are summed with Dalitz decay of the $\eta$, radiative decay of the $\Delta$ and from two-pion annihilation, the result matches recent high statistics proton-proton data from the Dilepton Spectrometer collaboration.Comment: 1+17 pages plus 11 PostScript figures uuencoded and appended, McGill/93-9, TPI-MINN-93/18-

Rate of photon production from hot hadronic matter

Thermal photon emission rates from hot hadronic matter are studied to order $e^{2}g^{4}$, where $g$ indicates a strong-interaction coupling constant. Radiative decay of mesons, Compton and annihilation processes for hadrons, and bremsstrahlung reactions are all considered. Compared to the standard rates from the literature, one finds two orders of magnitude increase for low photon energies stemming mainly from bremsstrahlung and then a modest increase (factor of 2) for intermediate and high energy photons owing to radiative decays for a variety of mesons and from other reactions involving strangeness. These results could have important consequences for electromagnetic radiation studies at RHIC.Comment: 5 pages LaTeX, 4 Postscript figure