The measurement of the 7Be(d,3He)6Li* transfer cross section at 5 MeV/u is carried out. The population of the 2.186 MeV excited state of 6Li in this reaction channel is observed for the first time. ...The experimental angular distributions have been analyzed in the finite range DWBA and coupled-channel frameworks. The effect of the 7Be(d,3He)6Li reaction on both the 6Li and 7Li abundances are investigated at the relevant big-bang nucleosynthesis energies. The excitation function is calculated by TALYS and normalized to the experimental data. The S factor of the (d,3He) channel from the present work is about 50% lower than existing data at nearby energies. At big-bang energies, the S factor is about three orders of magnitude smaller than that of the (d,p) channel. The (d,3He) reaction rate is found to have a less than 0.1% effect on the 6,7Li abundances.
The elastic and inelastic scattering of 7Be from 12C have been measured at an incident energy of 35 MeV. The inelastic scattering leading to the 4.439 MeV excited state of 12C has been measured for ...the first time. The experimental data cover an angular range of θcm = 15∘-120∘. Optical model analyses were carried out with Woods-Saxon and double-folding potential using the density dependent M3Y (DDM3Y) effective interaction. The microscopic analysis of the elastic data indicates breakup channel coupling effect. A coupled-channel analysis of the inelastic scattering, based on collective form factors, shows that mutual excitation of both 7Be and 12C is significantly smaller than the single excitation of 12C. The larger deformation length obtained from the DWBA analysis could be explained by including the excitation of 7Be in a coupled-channel analysis. The breakup cross section of 7Be is estimated to be less than 10% of the reaction cross section. The intrinsic deformation length obtained for the 12C⁎ (4.439 MeV) state is δ2 = 1.37 fm. The total reaction cross section deduced from the analysis agrees very well with Wong's calculations for similar weakly bound light nuclei on 12C target.
The measurement of the breakup of the radioactive nucleus 7Be on 12C at 5 MeV/u is reported for the first time. Significant coincidence counts of α and 3He from 7Be breakup have been identified. ...Analysis is ongoing to identify the breakup events from a direct or sequential process.
Phys. Lett. B 853 (2024) 138673 The measurement of the $^7$Be($d$,$^3$He)$^6$Li* transfer cross section at 5
MeV/u is carried out. The population of the 2.186 MeV excited state of $^6$Li
in this ...reaction channel is observed for the first time. The experimental
angular distributions have been analyzed in the finite range DWBA and
coupled-channel frameworks. The effect of the $^7$Be($d$,$^3$He)$^6$Li reaction
on both the $^6$Li and $^7$Li abundances are investigated at the relevant
big-bang nucleosynthesis energies. The excitation function is calculated by
TALYS and normalized to the experimental data. The $S$ factor of the
($d$,$^3$He) channel from the present work is about 50$\%$ lower than existing
data at nearby energies. At big-bang energies, the $S$ factor is about three
orders of magnitude smaller than that of the ($d,p$) channel. The ($d$,$^3$He)
reaction rate is found to have a less than 0.1$\%$ effect on the $^{6,7}$Li
abundances.
Physics Letters B 833(2022)137294 The elastic and inelastic scattering of $^7$Be from $^{12}$C have been
measured at an incident energy of 35 MeV. The inelastic scattering leading to
the 4.439 MeV ...excited state of $^{12}$C has been measured for the first time.
The experimental data cover an angular range of $\theta_{cm}$ =
15$^{\circ}$-120$^{\circ}$. Optical model analyses were carried out with
Woods-Saxon and double-folding potential using the density dependent M3Y
(DDM3Y) effective interaction. The microscopic analysis of the elastic data
indicates breakup channel coupling effect. A coupled-channel analysis of the
inelastic scattering, based on collective form factors, show that mutual
excitation of both $^7$Be and $^{12}$C is significantly smaller than the single
excitation of $^{12}$C. The larger deformation length obtained from the DWBA
analysis could be explained by including the excitation of $^7$Be in a
coupled-channel analysis. The breakup cross section of $^7$Be is estimated to
be less than 10$\%$ of the reaction cross section. The intrinsic deformation
length obtained for the $^{12}$C$^*$ (4.439 MeV) state is $\delta _2$ = 1.37
fm. The total reaction cross section deduced from the analysis agrees very well
with Wong's calculations for similar weakly bound light nuclei on $^{12}$C
target.
Physical Review Letters 128, 252701 (2022) The anomaly in lithium abundance is a well-known unresolved problem in
nuclear astrophysics. A recent revisit to the problem tried the avenue of
resonance ...enhancement to account for the primordial $^7$Li abundance in
standard big-bang nucleosynthesis (BBN). Prior measurements of the
$^7$Be(d,p)$^8$Be* reaction could not account for the individual contributions
of the different excited states involved, particularly at higher energies close
to the Q-value of the reaction. We carried out an experiment at HIE-ISOLDE,
CERN to study this reaction at E$_{cm}$ = 7.8 MeV, populating excitations up to
22 MeV in $^8$Be for the first time. The angular distributions of the several
excited states have been measured and the contributions of the higher excited
states in the total cross section at the relevant big-bang energies were
obtained by extrapolation to the Gamow window using the TALYS code. The results
show that by including the contribution of the 16.63 MeV state, the maximum
value of the total S-factor inside the Gamow window comes out to be 167 MeV b
as compared to earlier estimate of 100 MeV b. However, this still does not
account for the lithium discrepancy.
The measurement of the \(^7\)Be(\(d\),\(^3\)He)\(^6\)Li* transfer cross section at 5 MeV/u is carried out. The population of the 2.186 MeV excited state of \(^6\)Li in this reaction channel is ...observed for the first time. The experimental angular distributions have been analyzed in the finite range DWBA and coupled-channel frameworks. The effect of the \(^7\)Be(\(d\),\(^3\)He)\(^6\)Li reaction on both the \(^6\)Li and \(^7\)Li abundances are investigated at the relevant big-bang nucleosynthesis energies. The excitation function is calculated by TALYS and normalized to the experimental data. The \(S\) factor of the (\(d\),\(^3\)He) channel from the present work is about 50\(\%\) lower than existing data at nearby energies. At big-bang energies, the \(S\) factor is about three orders of magnitude smaller than that of the (\(d,p\)) channel. The (\(d\),\(^3\)He) reaction rate is found to have a less than 0.1\(\%\) effect on the \(^{6,7}\)Li abundances.
