Study of Cross-Section Fluctuations forLi6+C12Reactions

Abstract

Differential cross-section measurements for Li 6 +C 12 reactions are presented in 100-keV steps between 2.4 and 8.5 MeV at 0° and in 200-keV steps between 3.4 and 7.4 MeV at 40° (lab). Fluctuations in the cross sections are observed at all energies, but they are superimposed upon a rapid rise in cross section for beam energies below 4 MeV due to the Coulomb barrier effects. Coulomb barrier effects are accounted for by calculating the average differential cross section from the Hauser-Feshbach formula in which the transmission coefficients are determined from an optical-model potential. The ratios of the observed-to-calculated cross sections fluctuate about an almost constant value. These ratios are analyzed in terms of the Ericson fluctuation theory from which the coherence width is estimated to be ro=250 keV (cm.). The average cross-section ratio for the C 12 (Li 6 ,ai)N 14 reaction indicates a 30% violation of isobaric-spin conservation in the 3.4-to 6.0-MeV interval.

Application of the statistical model to the light heavy-ion system6Li +6Li

“…But, as a matter of fact, transmission coefficients of some hip-optical model potentials available in literature [45,46] exhibit just this particular behaviour at low energies, commonly referred to as "oddeven staggering". Such a behaviour of the potential is responsible for formerly made observations of parity dependent cross sections for states with equal spin J in the course of HF-calculations for the system t2C+OLi [4]. In our case, however, this explanation is not justified because of the rather large Q-values of the p and n-channels and the high energies of the outgoing particles.…”

Low-Energy Properties of RealisticN−NOne-Boson-Exchange Potentials

“…E VIDENCE for both compound nucleus and direct interaction has been observed in lithium-induced reactions, 1 particularly in the C 12 +Li 6 investigations, [2][3][4][5][6][7] in the Li 6 ' 7 +B 10 ' n investigations, 8,9 and in the Li 6 +Be 9 to additional types and ranges of experimental data. Were the objective of such efforts viewed from the * standpoint of particle physics where the N-N interac-3 tion is but one of many possible baryon-baryon interac-L tions, such tedious endeavors might not be worth while.…”

“…We shall confine our discussions to the models of Green and Sawada, particularly their simple two-parameter model, 3 which is fairly representative of their more precise seven-parameter models, 2 the Bryan-Scott (BS) III model, 4 and the Ueda-Green (UG) I model. 5 The last model, which has been adjusted to the most recent N-N phase shifts, 6 ' 7 will be given the greatest attention.…”

“…These models are based upon the exchange of pseudoscalar (P), vector (F), and scalar (5) mesons and all lead to a total potential V to t of the form given by Eq. (16) and Table I of Ref.…”

“…(16) and Table I of Ref. 5. All of these studies use generalized Yukawa potentials which are special cases of the "well-regulated" potential of Green and Sawada [see Eq.…”