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Mirror Nuclei - Isospin Symmetry Breaking in the Mass A=35 and A=51 Mirror Nuclei

Ekman, Jörgen LU (2004)
Abstract
High-spin states in the A=35 mirror nuclei 35Ar and 35Cl and A=51 mirror nuclei 51Fe and 51Mn were populated using fusion-evaporation reactions. The gamma rays were detected in the powerful Ge arrays Gammasphere and GASP, respectively, which operated in conjunction with ancillary detectors for evaporated particles.



The resulting mirror energy difference diagrams of the two mirror pairs are interpreted in terms of various electromagnetic effects and possible isospin-symmetry breaking components of the nuclear force. In the A=35 mirror nuclei effects of the electromagnetic spin-orbit interaction have been discriminated for the first time. In addition, an unusual decay pattern of excited states can give direct evidence on... (More)
High-spin states in the A=35 mirror nuclei 35Ar and 35Cl and A=51 mirror nuclei 51Fe and 51Mn were populated using fusion-evaporation reactions. The gamma rays were detected in the powerful Ge arrays Gammasphere and GASP, respectively, which operated in conjunction with ancillary detectors for evaporated particles.



The resulting mirror energy difference diagrams of the two mirror pairs are interpreted in terms of various electromagnetic effects and possible isospin-symmetry breaking components of the nuclear force. In the A=35 mirror nuclei effects of the electromagnetic spin-orbit interaction have been discriminated for the first time. In addition, an unusual decay pattern of excited states can give direct evidence on isospin mixing. Excited states in 51Fe have been observed for the first time. In the A=51 mirror nuclei detailed isospin-symmetry studies are performed including core-excited states. This mark the first comparison of such analogue states in mirror nuclei.



An extensive level scheme of the nucleus 51Mn has been constructed. It comprises approximately 50 previously unknown core excited states, which are interpreted in terms of comprehensive large shell-model calculations including electro-magnetic decay properties. In addition, a rotational band has been identified, which is interpreted using the cranked Nilsson-Strutinsky model and found to comprise a particle in the 1g9/2 intruder orbital. (Less)
Abstract (Swedish)
Popular Abstract in Swedish

Atomkärnan består av protoner och neutroner, gemensamt kallade nukleoner, vilka hålls samman via den starka kärnkraften. Denna är emellertid inte den enda aktiva kraften i atomkärnan, utan även Coulomb växelverkan mellan de positivt elektriskt laddade protonerna är närvarande. I frånvaro av Coulomb växelverkan skulle protonens och neutronens egenskaper vara väldigt lika och denna symmetri går under benämningen isospin symmetri. Coulomb växelverkan bryter denna symmetri och effekterna av symmetribrottet kan studeras i så kallade spegelkärnor, vilka är par av kärnor där antalet protoner och neutroner är det omvända. Ett exempel på spegelkärnor är 51Fe som har 26 protoner och 25 neutroner och 51Mn... (More)
Popular Abstract in Swedish

Atomkärnan består av protoner och neutroner, gemensamt kallade nukleoner, vilka hålls samman via den starka kärnkraften. Denna är emellertid inte den enda aktiva kraften i atomkärnan, utan även Coulomb växelverkan mellan de positivt elektriskt laddade protonerna är närvarande. I frånvaro av Coulomb växelverkan skulle protonens och neutronens egenskaper vara väldigt lika och denna symmetri går under benämningen isospin symmetri. Coulomb växelverkan bryter denna symmetri och effekterna av symmetribrottet kan studeras i så kallade spegelkärnor, vilka är par av kärnor där antalet protoner och neutroner är det omvända. Ett exempel på spegelkärnor är 51Fe som har 26 protoner och 25 neutroner och 51Mn som har 25 protoner och 26 neutroner. Genom att i diagramform presentera skillnaden i energi hos exciterade tillstånd i spegelkärnor som funktion av tillståndens rörelsemängdsmoment erhåller man ett så kallat MED (mirror energy difference) diagram. MED diagram är användbara vid studier av isospin symmetri-brott, men kan även användas för att studera nukleonkonfigurationer hos tillstånd.



I detta arbete presenteras nya resultat om spegelkärnor. Vid studier av deras respektive MED diagram framgår att hänsyn måste tas till effekter som traditionellt inte har studerats. Dessa innefattar eventuella bidrag från en komponent av den starka kärnkraften som är laddningsberoende, vilket innebär att växelverkan mellan två neutroner och två protoner är olika även i frånvaro av elektromagnetiska bidrag. Vidare visar arbetet, för första gången, att elektromagnetisk spin-ban koppling i vissa fall är en bidragande orsak till observerade MED diagram. Även bidrag vilka har sitt ursprung i förändringar av radien hos spegelkärnor diskuteras. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Prof Sharpey-Schafer, J.F., South Africa
organization
publishing date
type
Thesis
publication status
published
subject
keywords
high-spin states, shell-model calculations, fusion-evaporation reactions, Nuclear physics, Kärnfysik, Fysicumarkivet A:2004:Ekman, isospin symmetry, Mirror nuclei
pages
130 pages
publisher
Jörgen Ekman, Department of Physics, Box 118, SE-22100 Lund, Sweden,
defense location
Lecture Hall B, Department of Physics
defense date
2004-06-04 13:15:00
external identifiers
  • other:ISRN:LUNFD6/(NFFR-1024)/1-130/(2004)
ISBN
91-628-6061-5
language
English
LU publication?
yes
additional info
Article: 1. The A=51 Mirror Nuclei 51Fe and 51MnEur. Phys. J. A 9, 13 (2000).J. Ekman et al. Article: 2. Evidence for a 1g9/2 rotational band in 51MnPhys. Rev. C 66, 051301(R) (2002).J. Ekman et al. Article: 3. Unusual isospin-breaking and isospin-mixing effects in the A=35 mirror nucleiPhys. Rev. Lett. 92, 132502 (2004).J. Ekman et al. Article: 4. Gamma-ray spectroscopy of core-excited states in 51MnSubmitted to Phys. Rev. C.J. Ekman et al. Article: 5. Core excited states in the A=51 mirror nucleiTo be submitted to Eur. Phys. J.J. Ekman et al.
id
9d3df0c5-abb2-403b-af5d-ca0449065081 (old id 467069)
date added to LUP
2016-04-04 10:11:45
date last changed
2018-11-21 20:57:20
@phdthesis{9d3df0c5-abb2-403b-af5d-ca0449065081,
  abstract     = {High-spin states in the A=35 mirror nuclei 35Ar and 35Cl and A=51 mirror nuclei 51Fe and 51Mn were populated using fusion-evaporation reactions. The gamma rays were detected in the powerful Ge arrays Gammasphere and GASP, respectively, which operated in conjunction with ancillary detectors for evaporated particles.<br/><br>
<br/><br>
The resulting mirror energy difference diagrams of the two mirror pairs are interpreted in terms of various electromagnetic effects and possible isospin-symmetry breaking components of the nuclear force. In the A=35 mirror nuclei effects of the electromagnetic spin-orbit interaction have been discriminated for the first time. In addition, an unusual decay pattern of excited states can give direct evidence on isospin mixing. Excited states in 51Fe have been observed for the first time. In the A=51 mirror nuclei detailed isospin-symmetry studies are performed including core-excited states. This mark the first comparison of such analogue states in mirror nuclei.<br/><br>
<br/><br>
An extensive level scheme of the nucleus 51Mn has been constructed. It comprises approximately 50 previously unknown core excited states, which are interpreted in terms of comprehensive large shell-model calculations including electro-magnetic decay properties. In addition, a rotational band has been identified, which is interpreted using the cranked Nilsson-Strutinsky model and found to comprise a particle in the 1g9/2 intruder orbital.},
  author       = {Ekman, Jörgen},
  isbn         = {91-628-6061-5},
  language     = {eng},
  publisher    = {Jörgen Ekman, Department of Physics, Box 118, SE-22100 Lund, Sweden,},
  school       = {Lund University},
  title        = {Mirror Nuclei - Isospin Symmetry Breaking in the Mass A=35 and A=51 Mirror Nuclei},
  year         = {2004},
}