[1] OAK RIDGE NATL LAB, DIV PHYS, OAK RIDGE, TN 37830 USA
[2] CALTECH, WW KELLOGG RADIAT LAB, PASADENA, CA 91125 USA
[3] INST PHYS NUCL, DIV PHYS THEOR, F-91406 ORSAY, FRANCE
[4] CTR RECH NUCL, PHYS THEOR SERV, F-67037 STRASBOURG, FRANCE
[5] UNIV ILLINOIS, DEPT PHYS, CHICAGO, IL 60680 USA
[6] UNIV CALIF LAWRENCE LIVERMORE LAB, LIVERMORE, CA 94550 USA