# 7th International Conference on New Frontiers in Physics (ICNFP2018)

Jul 4 – 12, 2018
Europe/Athens timezone
Group photo: indico.cern.ch/event/663474/images/19808-ICNFP_2018_Group_Photo.JPG

## n + $^{7}$Be cross-sections of astrophysical interest at the CERN n_TOF facility

Jul 7, 2018, 3:00 PM
30m
Room 4

### Room 4

Oral presentation

### Speaker

Dr Mario Mastromarco (European Council for Nuclear Research (CERN) and University of Manchester (GB))

### Description

One of the most long-standing puzzles in nuclear astrophysics is the so-called “Cosmological Lithium Problem”. The standard Big Bang nucleosynthesis theory (BBN) predicts the abundances of the light elements $^{2}$H, $^{3}$He, $^{4}$He and $^{7}$Li produced in the early universe. The primordial abundances of $^{2}$H and $^{4}$He inferred from experimental data are in good agreement with predictions. On the contrary, the theory overestimates the primordial $^{7}$Li abundance by about a factor of three. In an attempt to solve this problem, a possible explanation was an incorrect estimation of the destruction rate from n + $^{7}$Be reactions, being the decay of $^{7}$Be responsible for the production of 95% of primordial Lithium. Data on the $^{7}$Be(n, α) and $^{7}$Be(n, p) reaction channels are scarce or inexistent, thus large uncertainty still affects the abundance of $^{7}$Li predicted by BBN theory. With the aim of obtaining reliable data on the n + $^{7}$Be reactions in a wide neutron energy range, two measurements have been performed at the n_TOF facility at CERN, taking advantage of the new high-flux experimental area (EAR2). New detectors have been specifically developed for these measurements, and new techniques employed for the production of high-purity $^{7}$Be samples. In particular, for the first time a neutron measurement has been performed on a sample produced by implantation of a radioactive beam at ISOLDE. In this talk, the experimental apparatus and sample preparation techniques will be presented, together with recent results on the $^{7}$Be(n, α) and $^{7}$Be(n, p) reactions and their implications on the Cosmological Lithium Problem.

### Primary authors

Dr Mario Mastromarco (European Council for Nuclear Research (CERN) and University of Manchester (GB)) Lucia Anna Damone (University and INFN, Bari (IT)) Massimo Barbagallo (University and INFN, Bari (IT)) Nicola Colonna (University and INFN, Bari (IT))

### Presentation materials

 Mastromarco.pdf Mastromarco.ppt