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

Area of Science:

• Nuclear astrophysics
• Big-bang nucleosynthesis
• Stellar nucleosynthesis

Background:

• The primordial lithium abundance anomaly is a persistent puzzle in nuclear astrophysics.
• Previous studies on the ^{7}Be(d,p)^{8}Be^{*} reaction lacked detailed contributions from excited states at higher energies.

Purpose of the Study:

• To investigate the ^{7}Be(d,p)^{8}Be^{*} reaction at E_{c.m.}=7.8 MeV.
• To measure contributions of excited states in ^{8}Be up to 22 MeV.
• To refine calculations for primordial ^{7}Li abundance in Big Bang nucleosynthesis.

Main Methods:

• Experiment conducted at HIE-ISOLDE, CERN.
• Measurement of angular distributions for ^{7}Be(d,p)^{8}Be^{*} reaction.
• Extrapolation to the Gamow window using the talys code.

Main Results:

• First-time population of ^{8}Be excitations up to 22 MeV.
• Inclusion of the 16.63 MeV state increased the total S factor to 167 MeV b (from 100 MeV b).
• The enhanced S factor still does not resolve the lithium abundance discrepancy.

Conclusions:

• The study provides crucial data on ^{8}Be excited states relevant to Big Bang nucleosynthesis.
• Resonance enhancement via the studied reaction channel does not fully explain the primordial lithium anomaly.
• Further research is needed to address the persistent lithium discrepancy in cosmological models.