Separation of Delta S=0 and Delta S=1 in the response of {sup 12}C to 318 MeV protons

Journal Article · Thu Apr 01 04:00:00 EST 1993 · Phys. Rev. C 48, 1106-1115 (1993)

OSTI ID:791698

Baker, F T; Beatty, D; Bimbot, L; Cupps, V; Djalali, C; Fergerson, R W; Glashausser, C; Graw, G; Green, A; Jones, K; Morlet, M; Nanda, S K; Sethi, A; Storm, B H; Unkelbach, W; Willis, and A

Angular distributions of the double-differential cross section d{sup 2} sigma/d Omega dE (sigma) and the spin-flip probability S{sub nn} have been measured for inclusive inelastic proton scattering from {sup 12}C at E{sub p}=318 MeV. Data have been obtained over an excitation energy range 9 MeV {le} E{sub x} {le} 42 MeV for laboratory scattering angles of 3{sup o}, 5{sup o}, 7{sup o}, 9{sup o}, 12{sup o}, 15{sup o}, and 18{sup o}. Multipole decompositions of angular distributions of both the spin-flip cross section sigma {sub SF} = sigma S{sub nn} and the estimated cross section for Delta S=0 transitions have been performed. The distribution of deduced Delta L=1, Delta S=0 (the giant-dipole resonance) strength peaks near E{sub x}=22 MeV; although there is apparently much more strength relative to the energy-weighted sum rule (EWSR) than expected, this appears to be an artifact of instrumental background at small angles. Approximately 55% of the EWSR for Delta L=2, Delta S=0 was observed spread uniformly across the spectrum with no evidence for a giant-quadrupole resonance. Angular distributions for sigma{sub SF} were analyzed using the predictions from random-phase approximation calculations for the nuclear structure and distorted-wave impulse approximation calculations for the scattering. These predictions are found to provide a good description of the sigma{sub SF} data above E{sub x}=25 MeV; values of S{sub nn} are predicted somewhat too low in this region.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA (US)
• Sponsoring Organization: USDOE Office of Energy Research (ER) (US)
• DOE Contract Number: AC05-84ER40150
• OSTI ID: 791698
• Report Number(s): CEBAF-PR-93-050; DOE/ER/40150-2000
• Journal Information: Phys. Rev. C 48, 1106-1115 (1993), Journal Name: Phys. Rev. C 48, 1106-1115 (1993)
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
CARBON 12
CROSS SECTIONS
ENERGY RANGE
IMPULSE APPROXIMATION
NUCLEAR STRUCTURE
PROTONS
SCATTERING
SPIN FLIP
SUM RULES