Resonance Excitations in 7Be(d,p)8Be*to Address the Cosmological Lithium Problem

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. 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 c . m . = 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 authors thank the ISOLDE engineers in charge, RILIS team and Target Group at CERN for their support. D. G. acknowledges research funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 654002 (ENSAR2) and ISRO, Government of India under Grant No. ISRO/RES/2/378/15-16. O. T. would like to acknowledge the support by the Spanish Funding Agency (AEI/FEDER, EU) under the project PID2019-104390GB-I00. I. M. would like to acknowledge the support by the Ministry of Science, Innovation and Universities of Spain (Grant No. PGC2018-095640-B-I00). J. C. acknowledges grants from the Swedish Research Council (VR) under Contracts No. VR-2017-00637 and No. VR-2017-03986 as well as grants from the Royal Physiographical Society. J. P. would like to acknowledge the support by Institute for Basic Science (IBS-R031-D1). S. S. acknowledges support by the Academy of Finland (Grant No. 307685)

An experimental study of the rearrangements of valence protons and neutrons amongst single-particle orbits during double {\beta} decay in 100Mo

The rearrangements of protons and neutrons amongst the valence single-particle orbitals during double {\beta} decay of 100Mo have been determined by measuring cross sections in (d,p), (p,d), (3He,{\alpha}) and (3He,d) reactions on 98,100Mo and 100,102Ru targets. The deduced nucleon occupancies reveal significant discrepancies when compared with theoretical calculations; the same calculations have previously been used to determine the nuclear matrix element associated with the decay probability of double {\beta} decay of the 100Mo system.Comment: 18 pages, 13 figures, 37 pages of supplemental informatio

Resonance Excitations in Be 7 (d,p) Be∗ 8 to Address the Cosmological Lithium Problem

6 pags., 5 figs., 3 tabs.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 Li7 abundance in standard big-bang nucleosynthesis. Prior measurements of the Be7(d,p)Be∗8 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 Ec.m.=7.8 MeV, populating excitations up to 22 MeV in Be8 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.D. G. acknowledges research funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 654002 (ENSAR2) and ISRO, Government of India under Grant No. ISRO/RES/2/378/ 15–16. O. T. would like to acknowledge the support by the Spanish Funding Agency (AEI/FEDER, EU) under the project PID2019–104390GB-I00. I. M. would like to acknowledge the support by the Ministry of Science, Innovation and Universities of Spain (Grant No. PGC2018-095640-B-I00). J. C. acknowledges grants from the Swedish Research Council (VR) under Contracts No. VR-2017-00637 and No. VR-2017-03986 as well as grants from the Royal Physiographical Society. J. P. would like to acknowledge the support by Institute for Basic Science (IBS-R031-D1). S. S. acknowledges support by the Academy of Finland (Grant No. 307685)

Change of nuclear configurations in the neutrinoless double-β\beta decay of 130^{130}Te →\rightarrow 130^{130}Xe and 136^{136}Xe →\rightarrow 136^{136}Ba

The change in the configuration of valence protons between the initial and final states in the neutrinoless double-$\beta$ decay of $^{130}$Te $\rightarrow$ $^{130}$Xe and of $^{136}$Xe $\rightarrow$ $^{136}$Ba has been determined by measuring the cross sections of the ($d$,$^3$He) reaction with 101-MeV deuterons. Together with our recent determination of the relevant neutron configurations involved in the process, a quantitative comparison with the latest shell-model and interacting-boson-model calculations reveals significant discrepancies. These are the same calculations used to determine the nuclear matrix elements governing the rate of neutrinoless double-$\beta$ decay in these systems.Comment: 10 pages, 4 figures, 9 table

Study of elastic and inelastic scattering of 7Be + 12C at 35 MeV

6 pags., 5 figs., 2 tabs.The elastic and inelastic scattering of Be from C have been measured at an incident energy of 35 MeV. The inelastic scattering leading to the 4.439 MeV excited state of C has been measured for the first time. The experimental data cover an angular range of θ = 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 Be and C is significantly smaller than the single excitation of C. The larger deformation length obtained from the DWBA analysis could be explained by including the excitation of Be in a coupled-channel analysis. The breakup cross section of Be is estimated to be less than 10% of the reaction cross section. The intrinsic deformation length obtained for the C (4.439 MeV) state is δ = 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 C target.D. Gupta acknowledges research funding from the European Union's Horizon 2020 research and innovation programme under grant agreement no. 654002 (ENSAR2) and ISRO, Government of India under grant no. ISRO/RES/2/378/15-16. O. Tengblad would like to acknowledge the support by the Spanish Funding Agency (AEI / FEDER, EU) under the project PID2019-104390GB-I00. I. Martel would like to acknowledge the support by the Ministry of Science, Innovation and Universities of Spain (Grant No. PGC2018-095640-B-I00). J. Cederkall acknowledges grants from the Swedish Research Council (VR) under contract numbers VR-2017-00637 and VR-2017-03986 as well as grants from the Royal Physiographical Society. J. Park would like to acknowledge the support by Institute for Basic Science (IBS-R031-D1). S. Szwec acknowledges support by the Academy of Finland (Grant No. 307685). A.M.M. is supported by the I+D+i project PID2020-114687GB-I00 funded by MCIN/AEI/10.13039/501100011033, by the grant Group FQM-160 and by project P20_01247, funded by the Consejería de Economía, Conocimiento, Empresas y Universidad, Junta de Andalucía (Spain) and by “ERDF A way of making Europe”

Study of elastic and inelastic scattering of 7^7Be + 12^{12}C at 35 MeV

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.Comment: 8 pages, 5 figure

Neutron occupancies and single-particle energies across the stable tin isotopes

The occupancies and vacancies of the valence neutron orbitals across the stable tin isotopic chain from $112\leq A\leq 124$ have been determined. These were inferred from the cross sections of neutron-adding and -removing reactions. In each case, the reactions were chosen to have good angular-momentum matching for transfer to the low- and high-$\ell$ orbitals present in this valence space. These new data are compared to older systematic studies. The effective single-neutron energies are determined by combining information from energy centroids determined from the adding and removing reactions. Two of the five orbitals are nearly degenerate, below $N=64$, and approximately two MeV more bound than the other three, which are also degenerate.Comment: 11 pages, 10 figure

Experimental study of the rearrangements of valence protons and neutrons amongst single-particle orbits during double-β decay in 100Mo

The rearrangements of protons and neutrons amongst the valence single-particle orbitals during double-β decay of Mo100 have been determined by measuring cross sections in (d,p), (p,d), (He3,α), and (He3,d) reactions on Mo98,100 and Ru100,102 targets. The deduced nucleon occupancies reveal significant discrepancies when compared with theoretical calculations; the same calculations have previously been used to determine the nuclear matrix element associated with the decay probability of double-β decay of the Mo100 system.This material is based upon work supported by the UK Science and Technology Facilities Council, the US Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357, the National Science Foundation Grant No. PHY-08022648 (JINA), and the Deutsche Forschungsgemeinschaft Cluster of Excellence “Origin and Structure of the Universe.

The JUROGAM 3 spectrometer

The jurogam 3 spectrometer has been constructed for in-beam gamma-ray spectroscopy experiments in the Accelerator Laboratory of the University of Jyvaskyla, Finland. jurogam 3 consists of germanium-detector modules in a compact geometry surrounding a target to measure. rays emitted from radioactive nuclei. jurogam 3 can be employed in conjunction with one of two recoil separators, the mara vacuum-mode separator or the ritu gas-filled separator, and other ancillary devices.Peer reviewe