Spectroscopy of Lambda-9Li by electroproduction
nucl-ex
/ Authors
G. M. Urciuoli, F. Cusanno, S. Marrone, A. Acha, P. Ambrozewicz, K. A. Aniol, P. Baturin, P. Y. Bertin, H. Benaoum, K. I. Blomqvist
and 88 more authors
W. U. Boeglin, H. Breuer, P. Brindza, P. Bydzovsky, A. Camsonne, C. C. Chang, J. -P. Chen, Seonho Choi, E. A. Chudakov, E. Cisbani, S. Colilli, L. Coman, B. J. Craver, G. De Cataldo, C. W. de Jager, R. De Leo, A. P. Deur, C. Ferdi, R. J. Feuerbach, E. Folts, R. Fratoni, S. Frullani, F. Garibaldi, O. Gayou
/ Abstract
In the absence of accurate data on the free two-body hyperon-nucleon interaction, the spectra of hypernuclei can provide information on the details of the effective hyperon-nucleon interaction. Electroproduction of the hypernucleus Lambda-9Li has been studied for the first time with sub-MeV energy resolution in Hall A at Jefferson Lab on a 9Be target. In order to increase the counting rate and to provide unambiguous kaon identification, two superconducting septum magnets and a Ring Imaging CHerenkov detector (RICH) were added to the Hall A standard equipment. The cross section to low-lying states of Lambda-9Li is concentrated within 3 MeV of the ground state and can be fitted with four peaks. The positions of the doublets agree with theory while a disagreement could exist with respect to the relative strengths of the peaks in the doublets. A Lambda separation energy of 8.36 +- 0.08 (stat.) +- 0.08 (syst.) MeV was measured, in agreement with an earlier experiment.