Role of the Δ Resonance in the Population of a Four-Nucleon State in the 56Fe → 54Fe Reaction at Relativistic Energies

Summary, in English

The Fe54 nucleus was populated from a 56Fe beam impinging on a Be target with an energy of E/A=500 MeV. The internal decay via γ-ray emission of the 10+ metastable state was observed. As the structure of this isomeric state has to involve at least four unpaired nucleons, it cannot be populated in a simple two-neutron removal reaction from the 56Fe ground state. The isomeric state was produced in the low-momentum (-energy) tail of the parallel momentum (energy) distribution of 54Fe, suggesting that it was populated via the decay of the Δ0 resonance into a proton. This process allows the population of four-nucleon states, such as the observed isomer. Therefore, it is concluded that the observation of this 10+ metastable state in 54Fe is a consequence of the quark structure of the nucleons.

• Author: Zs Podolyák; C. M. Shand; Natasa Lalovic; J. Gerl; D. Rudolph; T. Alexander; P. Boutachkov; M. L. Cortés; M. Górska; I. Kojouharov; N. Kurz; C. Louchart; E. Merchán; C. Michelagnoli; R. M. Pérez-Vidal; S. Pietri; D. Ralet; M. Reese; H. Schaffner; Ch Stahl; H. Weick; F. Ameil; G. De Angelis; T. Arici; R. Carroll; Zs Dombrádi; A. Gadea; P. Golubev; M. Lettmann; C. Lizarazo; D. Mahboub; H. Pai; Z. Patel; N. Pietralla; P. H. Regan; L. G. Sarmiento; O. Wieland; E. Wilson; B. Birkenbach; B. Bruyneel; I. Burrows; L. Charles; E. Clément; F. C L Crespi; D. M. Cullen; P. Désesquelles; J. Eberth; V. González; T. Habermann; L. Harkness-Brennan; H. Hess; D. S. Judson; A. Jungclaus; W. Korten; M. Labiche; A. Maj; D. Mengoni; D. R. Napoli; A. Pullia; B. Quintana; G. Rainovski; P. Reiter; M. D. Salsac; E. Sanchis; J. J. Valiente Dóbon
• Department/s: Nuclear physics
• Publishing year: 2016-11-23
• Language: English
• Publication/Series: Physical Review Letters
• Volume: 117
• Issue: 22
• Full text: - 579 kB; Download statistics
• Links: http://dx.doi.org/10.1103/PhysRevLett.117.222302
• Document type: Journal article
• Publisher: American Physical Society
• Topic: Subatomic Physics
• Keywords: isomer decay; gamma-ray spectroscopy; relativistic projectile fragmentation
• Status: Published
• Project: Nuclear Structure at the Limits: Isotope-selective Spectroscopy; FAIR-NUSTAR: HISPEC-DESPEC experiment & Super-FRS contributions; Nuclear Structure Studies near 208Pb and gamma-ray Imaging Techniques
• ISBN/ISSN/Other: ISSN: 0031-9007