Neutron-neutron scattering length from the He-6(p, p alpha)nn reaction

Autor(es)

Goebel, Matthias ^[1] ; Aumann, Thomas ^{[1, 2, 3]} ; Bertulani, Carlos A. ^[4] ; Frederico, Tobias ^[5] ; Hammer, Hans-Werner ^{[1, 3, 6]} ; Phillips, Daniel R. ^{[7, 8, 1, 6]}

Afiliação do(s) autor(es)

^[1] Tech Univ Darmstadt, Dept Phys, Inst Kernphys, D-64289 Darmstadt - Germany

^[2] GSI Helmholtzzentrum Schwerionenforsch GmbH, Planckst 1, D-64291 Darmstadt - Germany

^[3] Helmholtz Res Acad FAIR, D-64291 Darmstadt - Germany

^[4] Texas A&M Univ Commerce, Dept Phys & Astron, Commerce, TX 75429 - USA

^[5] DCTA, Inst Tecnol Aeronaut, BR-12228900 Sao Jose Dos Campos, SP - Brazil

^[6] GSI Helmholtzzentrum Schwerionenforsch GmbH, ExtreMe Matter Inst EMMI, D-64291 Darmstadt - Germany

^[7] Ohio Univ, Dept Phys & Astron, Athens, OH 45701 - USA

^[8] Ohio Univ, Inst Nucl & Particle Phys, Athens, OH 45701 - USA

• Tipo de documento: Artigo Científico
• Fonte: Physical Review C; v. 104, n. 2 AUG 9 2021.
• Citações Web of Science: 0

Resumo

We propose a novel method to measure the neutron-neutron scattering length using the He-6(p, p alpha)nn reaction in inverse kinematics at high energies. The method is based on the final-state interaction (FSI) between the neutrons after the sudden knockout of the alpha particle. We show that the details of the neutron-neutron relative-energy distribution allow for a precise extraction of the s-wave scattering length. We present the state of the art in regard to the theory of this distribution. The distribution is calculated in two steps. First, we calculate the ground-state wave function of He-6 as a ann three-body system. For this purpose we use Halo effective field theory, which also provides uncertainty estimates for the results. We compare our results at this stage to model calculations done with the computer code FaCE. In a second step we determine the effects of the nn FSI using the nn t-matrix. We compare these FSI results to approximate FSI approaches based on standard FSI enhancement factors. While the final distribution is sensitive to the nn scattering length, it depends only weakly on the effective range. Throughout we emphasize the impact of theoretical uncertainties on the neutron-neutron relative-energy distribution, and discuss the extent to which those uncertainties limit the extraction of the neutron-neutron scattering length from the reaction He-6(p, p alpha)nn. (AU)

• Processo FAPESP: 17/05660-0 - Estudos teóricos da estrutura e reações de núcleos exóticos e sistemas de muitos corpos
• Beneficiário: Brett Vern Carlson
• Modalidade de apoio: Auxílio à Pesquisa - Temático