Resonance states of Ps- using correlated wave functions
Abstract We have investigated the F e 1 , 3 resonance states of positronium negative ion below the N = 3 , 4 and 5 Ps thresholds using highly correlated exponential wave functions. Resonance parameters (positions and widths) are extracted employing both the stabilization method and the complex-coordinate rotation method. In addition to many Feshbach resonances below the various Ps thresholds, we have identified two F e 1 shape resonances with one each lying above the N = 3 and N = 5 thresholds, respectively. We have also identified three F e 3 shape resonances with one lying above the N = 3 threshold and two lying above N = 4 threshold. The F e 1 , 3 shape resonances associated with N = 3 Ps threshold and some other Feshbach resonances are reported for the first time in the literature.
Resonances in Three-Body Atomic Systems Involving Positrons
We review the theoretical studies of atomic resonances in three-body systems in-volving positrons. These works employ a method of complex-coordinate rotation. In-vestigations on resonances in positron-hydrogen scattering below various hydrogen andpositronium thresholds are discussed, as well as resonances in e+-He+ scattering. Fur-thermore, resonances in electron-positronium scattering will also be reviewed. Thetheoretical results for doubly-excited states of Ps- reveal the supermultiplete struc-tures of such an ion, and its tri-atomic molecular characters in analogy to an XYXmolecule.PACS. 31.15.Ar - Ab initio calculations.PACS. 32.80.D~ - Autoionization.
Parameters for low energy operation of CESR
We present a detailed design for operation of the Cornell Electron Storage Ring, CESR, in the energy range covering the /spl psi/ resonances and the Charm and Tau thresholds, as well as reaching to the upper Y resonances near 11 GeV. The addition of 18 m of super-ferric wiggler magnets will partially restore low energy beam emittance and damping times. Installation of superconducting quadrupoles in the interaction region and the addition of high performance superconducting RF cavities will enhance performance at all energies. Studies of optics, beam dynamics, wiggler and vacuum system performance, beam stability, and beam-beam effects confirm operation with a luminosity of 3/spl times/ 10/sup 32/ CM/sup -2/ sec/sup -1/ at 1.88 GeV.