Coulomb breakup of {sup 7}Li for nuclear astrophysics

Journal Article · Thu Mar 01 04:00:00 EST 2001 · Physical Review C

DOI:https://doi.org/10.1103/PhysRevC.63.035801· OSTI ID:40206160

Tokimoto, Y; Utsunomiya, H; Yamagata, T; Ohta, M; Lui, Y -W; Schmitt, R P; Typel, S; Aoki, Y; Ieki, K; Katori, K

A new Coulomb breakup experiment was performed for {sup 7}Li with an improved experimental technique and theoretical treatment. Energy spectra of {alpha} particles and tritons were examined to find the signature of post-Coulomb acceleration in the breakup of {sup 7}Li at E{sub {alpha}t}=0. The data revealed the delayed nature of nonresonant breakup of astrophysical relevance that stems from quantum tunneling. Semiclassical discussions are presented of the lifetime of continuum states in {sup 7}Li and distortion of relative kinetic energies between {alpha} and t by post-Coulomb acceleration. Dynamical calculations of Coulomb breakup were performed by solving a time-dependent Schro''dinger equation. A simple potential model of {sup 7}Li was employed. The dynamical calculations reasonably reproduced experimental cross sections for both resonant and nonresonant breakup with two key ingredients: higher order effects and mixture of E1 and E2 multipoles. Considering the dominant role of the first-order E1 nature in adiabatic Coulomb breakup, cross sections in the v{sub {alpha}}{>=}v{sub t} branch at 7{sup o}--15{sup o} for {sup 64}Zn and {sup 90}Zr were used to deduce astrophysical S factors S(E) for t({alpha},{gamma}){sup 7}Li. They exhibit a moderate energy dependence at small energies. The strongly energy-dependent S(E) resulted from the previous Coulomb breakup experiment based on cross sections with v{sub {alpha}}{<=}v{sub t}; they are most likely Coulomb distorted and are revised in the present work.

• Sponsoring Organization: (US)
• OSTI ID: 40206160
• Journal Information: Physical Review C, Journal Name: Physical Review C Journal Issue: 3 Vol. 63; ISSN 0556-2813
• Publisher: The American Physical Society
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACCELERATION
ASTROPHYSICS
CROSS SECTIONS
ENERGY DEPENDENCE
ENERGY SPECTRA
KINETICS
LIFETIME
MIXTURES
MULTIPOLES
TRITONS
TUNNELING