The Use of the Scattering Phase Shift in Resonance Physics

The scattering phase shift encodes a good amount of physical information which can be used to study resonances from scattering data. Among others, it can be used to calculate the continuum density of states and the collision time in a resonant process. Whereas the first information can be employed to examine the evolution of unstable states directly from scattering data, the second one serves as a tool to detect resonances and their properties. We demonstrate both methods concentrating in the latter case on 'exotic' resonances in pi-pi and pi-K scattering.Comment: Talk given at the International Workshop PENTAQUARK04, July 20-23 at Spring-8, Japan (new references added

Faraday's law in the presence of magnetic monopoles

We show that if we consider the full statement of Faraday's law for a closed physical circuit, the standard Maxwell's equations in the presence of electric and magnetic charges have to include in their integral form a mixed term of the form $\rho_m {\bf v}_e^{\perp}$ where $\rho_m$ is the magnetic charge density and ${\bf v}_e^{\perp}$ the perpendicular component of the velocity ${\bf v}_e$ of the electric charge.Comment: 9 page

Pentaquark Resonances from Collision Times

Having successfully explored the existing relations between the S-matrix and collision times in scattering reactions to study the conventional baryon and meson resonances, the method is now extended to the exotic sector. To be specific, the collision time in various partial waves of K+ N elastic scattering is evaluated using phase shifts extracted from the K+ N --> K+ N data as well as from model dependent T-matrix solutions. We find several pentaquark resonances including some low-lying ones around 1.5 to 1.6 GeV in the P_01, P_03 and D_03 partial waves of K+ N elastic scattering.Comment: Talk given at the International Workshop PENTAQUARK04, July 20-23 at Spring-8, Japa

Deuteron properties from muonic atom spectroscopy

Leading order ($\alpha^4$) finite size corrections in muonic deuterium are evaluated within a few body formalism for the $\mu^- p n$ system in muonic deuterium and found to be sensitive to the input of the deuteron wave function. We show that this sensitivity, taken along with the precise deuteron charge radius determined from muonic atom spectroscopy can be used to determine the elusive deuteron D-state probability, $P_D$, for a given model of the nucleon-nucleon (NN) potential. The radius calculated with a $P_D$ of 4.3\% in the chiral NN models and about 5.7\% in the high precision NN potentials is favoured most by the $\mu^-d$ data.Comment: 14 pages, 2 figure

Possible eta-mesic 3He states within the finite rank approximation

We extend the method of time delay proposed by Eisenbud and Wigner, to search for unstable states formed by eta mesons and the 3He nucleus. Using few body equations to describe eta-3He elastic scattering, we predict resonances and unstable bound states within different models of the eta-N interaction. The eta-3He states predicted within this novel approach are in agreement with the recent claim of the evidence of eta-mesic 3He made by the TAPS collaboration.Comment: 10 pages LaTex, 3 figure