arXiv subjects
Publications and source records attributed to H. Krauss.
The $α$--$α$ differential cross sections are analyzed in the optical model using a double--folded potential. With the knowledge of this potential bound and resonance--state properties of $α$--cluster states in $^{8}$Be and $^{12}$C as well as astrophysical S--factors of $^{4}$He($α$,$γ$)$^{8}$Be and $^{8}$Be($α$,$γ$)$^{12}$C are calculated. $Γ_γ$--widths and B(E2)--values are deduced.
The astrophysical S--factor and reaction rates for the triple--alpha process are calculated in the direct--capture model. It is shown that the stellar carbon production is extremely sensitive to small variations in the N--N interaction.
The $α$--$α$ differential cross sections are analyzed in the optical model using a double--folded potential. With the knowledge of this potential bound and resonance--state properties of $α$--cluster states in $^{8}$Be and $^{12}$C as well as astrophysical S--factors of $^{4}$He($α$,$γ$)$^{8}$Be and $^{8}$Be($α$,$γ$)$^{12}$C are calculated. $Γ_γ$--widths and B(E2)--values are deduced.
Differential cross sections for $^3$He-$α$ scattering were measured in the energy range up to 3 MeV. These data together with other available experimental results for $^3$He $+ α$ and $^3$H $+ α$ scattering were analyzed in the framework of the optical model using double-folded potentials. The optical potentials obtained were used to calculate the astrophysical S-factors of the capture reactions $^3$He$(α,γ)^7$Be and $^3$H$(α,γ)^7$Li, and the branching ratios for the transitions into the two final $^7$Be and $^7$Li bound states, respectively. For $^3$He$(α,γ)^7$Be excellent agreement between calculated and experimental data is obtained. For $^3$H$(α,γ)^7$Li a $S(0)$ value has been found which is a factor of about 1.5 larger than the adopted value. For both capture reactions a similar branching ratio of $R = σ(γ_1)/σ(γ_0) \approx 0.43$ has been obtained.
The astrophysical $S$-factor for the reaction $^7$Be(p,$γ$)$^8$B up to an energy of 2~MeV (c.m.) and the capture cross section of $^7$Li(n,$γ$)$^8$Li up to 1~MeV (c.m.) are calculated using the Direct Capture model (DC). Both calculations are in good agreement with experimental data.