121711369
Inversion of triton moments
We use the formalism of hyperspherical harmonics to calculate several moments for the triton photoeffect, for a Volkov spin-independent potential. First, we improve the accuracy of Maleki's calculations of the moments sigma/sub 2/ and sigma/sub 3/ by including more terms in the hyperspherical expansion. We also calculate moments sigma/sub 0/ and sigma/sub 1/ for a Serber mixture. We find reasonable agreement between our moments found by sum rules and those found from the cross sections calculated by Fang et al. and Levinger-Fitzgibbon. We then develop a technique of inversion of a finite number of moments by making the assumption that the cross section can be written as a sum of several Laguerre polynomials multiplied by a decreasing exponential. We test our inversion technique successfully on several model potentials. We then modify it and apply it to the five moments (sigma/sub -/1 to sigma/sub 3/) for a force without exchange, and find fair agreement with Fang's values of the cross section. Finally, we apply the inversion technique to our three moments (sigma/sub -/1, sigma/sub 0/, and sigma/sub 1/) for a Serber mixture, and find reasonable agreement with Gorbunov's measurements of the /sup 3/He photoeffect.
35585412
Hypertriton and hyperspherical harmonics.
We study the hypertriton using the formalism of hyperspherical harmonics, for spin-independent NN and N..lambda.. two-body potentials of Gaussian shape. We use up to 19 Simonov harmonics for the Verma-Sural potential, and obtain a ground state energy 240 keV below their value of -2.35 MeV found for 9 Simonov harmonics. The partial waves are used to calculate various expectation values for the hypertriton. We readjust the strength of the ..lambda..N potential to obtain agreement between the calculated energy and the experimental value.
40487262
Pion production as a test of nuclear matter properties.
Nuclear matter equations of state are constructed which incorporate explicitly the pion and delta degrees of freedom. These are used in relativistic one-dimensional and three-dimensional hydrodynamical models of central nucleus-nucleus collisions to determine the influence of the compressional energy on the observed pion multiplicity. We find a modest dependence on the compressional energy but a significant difference between slab-slab and sphere-sphere collisions having to do with curved shock waves. Thus one-dimensional hydrodynamic models do not appear to be suitable for interpreting pion production at energies of 100 MeV-2 GeV.
117724376
LEP Electroweak Physics Results
120522308
High energy cosmic muons and the calibration of the L3 electromagnetic calorimeter
Abstract A method to calibrate the L3 electromagnetic calorimeter with cosmic muons has been tested on a matrix of 100 tapered BGO crystals. Calibration constants in the energy range of 20–30 MeV were measured at the 2% level collecting about 200 muons per crystal. The results are in agreement with the calibration constant determined using a 10 GeV electron beam.
121495790
Ionization loss in BGO
Abstract We report on a precise measurement of the energy loss through ionization by pions in bismuth germanate performed at several values of the incident particles momentum with a prototype of the L3 electromagnetic calorimeter. The experimental results are in good agreement with theoretical predictions showing the relativistic rise modified by density effect.
118161147
ANALYSIS OF THE ETA PI0 PI0 FINAL STATE IN PHOTON-PHOTON COLLISIONS.
123816489
Single electron beams from the LEP pre-injector
At the request of the L3 collaboration (one of the LEP (Linear Electron-Positron collider) experiments) a new facility was built to close to the Electron Positron Accumulator (EPA) to provide a single electron per beam pulse at an energy which can be selected between 180 MeV and 500 MeV. The intensity of the ejected electron beam is reduced by changing the gun parameters and by adjusting the aperture of the slits in the linac. The energy is defined by letting the beam do 1/sup 1/4/ turn in the EPA. The energy spread is limited to +or-0.5*10/sup -3/ by reducing the slits aperture in the LIL/EPA transfer line. A new transfer line was built to transport the beam from the EPA ejection septum to the detector test stand. The facility was then used to test the response of the L3 electromagnetic calorimeter composed of bismuth-germanium-oxide crystals in the 100-MeV range.<<ETX>>