| Records |
Author  |
Fujita, Y. et al; Algora, A.; Estevez-Aguado, E.; Molina, F.; Rubio, B. |
| Title |
Observation of Low- and High-Energy Gamow-Teller Phonon Excitations in Nuclei |
Type |
Journal Article |
| Year |
2014 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
| Volume |
112 |
Issue |
11 |
Pages |
112502 - 5pp |
| Keywords |
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| Abstract |
Gamow-Teller (GT) transitions in atomic nuclei are sensitive to both nuclear shell structure and effective residual interactions. The nuclear GT excitations were studied for the mass number A = 42, 46, 50, and 54 “f-shell” nuclei in (He-3, t) charge-exchange reactions. In the Ca-42 -> Sc-42 reaction, most of the GT strength is concentrated in the lowest excited state at 0.6 MeV, suggesting the existence of a low-energy GT phonon excitation. As A increases, a high-energy GT phonon excitation develops in the 6-11 MeV region. In the Fe-54 -> Co-54 reaction, the high-energy GT phonon excitation mainly carries the GT strength. The existence of these two GT phonon excitations are attributed to the 2 fermionic degrees of freedom in nuclei. |
| Address |
[Fujita, Y.; Fujita, H.; Adachi, T.; Fujita, K.; Hatanaka, K.; Hirota, K.; Ishikawa, D.; Matsubara, H.; Nakanishi, K.; Okamura, H.; Ong, H. J.; Shimizu, Y.; Suzuki, T.; Tameshige, Y.; Tamii, A.; Uchida, M.; Wakasa, T.; Yosoi, M.; Zenihiro, J.] Osaka Univ, Nucl Phys Res Ctr, Ibaraki, Osaka 5670047, Japan, Email: fujita@rcnp.osaka-u.ac.jp |
| Corporate Author |
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Thesis |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0031-9007 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000332925900009 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1729 |
| Permanent link to this record |
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| Author |
Fujita, Y. et al; Algora, A.; Estevez-Aguado, E.; Molina, F.; Rubio, B. |
| Title |
High-resolution study of T-z =+2 ->+1 Gamow-Teller transitions in the Ca-44(3He,t)Sc-44 reaction |
Type |
Journal Article |
| Year |
2013 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
88 |
Issue |
1 |
Pages |
014308 - 18pp |
| Keywords |
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| Abstract |
In order to study the Gamow-Teller (GT) transitions from the T-z = +2 nucleus Ca-44 to the T-z = +1 nucleus Sc-44, where T-z is the z component of isospin T, we performed the (p, n)-type (He-3, t) charge-exchange (CE) reaction at 140 MeV/nucleon and the scattering angles 0 degrees and 2.5 degrees. An energy resolution of 28 keV, that was realized by applying matching techniques to the magnetic spectrometer system, allowed the study of fragmented states. The GT transition strengths, B(GT), were derived up to the excitation energy (E-x) of 13.7 MeV assuming the proportionality between cross sections and B(GT) values. The total sum of B(GT) values in discrete states was 3.7, which was 31% of the sum-rule-limit value of 12. Shell model calculations using the GXPF1J interaction could reproduce the gross features of the experimental B(GT) distribution, but not the fragmentation of the strength. By introducing the concepts of isospin, properties of isospin analogous transitions and states were investigated. (i) Assuming isospin symmetry, the T-z = +2 -> +1 and T-z = -2 -> -1 mirror GT transitions should have the same properties, where the latter can be studied in the beta decay of Cr-44 to V-44. First, we confirmed that the beta-decay half-life T-1/2 of Cr-44 can be reproduced using the B(GT) distribution from the Ca-44(He-3, t) measurement. Then, the 0 degrees, (3He, t) spectrum was modified to deduce the “beta-decay spectrum” and it was compared with the delayed-proton spectrum from the Cr-44 beta decay. The two spectra were mostly in agreement for the GT excitations, but suppression of the proton decay was found for the T = 2 isobaric analog state (IAS). (ii) Starting from the T = 2 ground state of 44Ca, the (3He, t) can excite GT states (state populated by GT transitions) with T = 1, 2, and 3. On the other hand, the Ca-44(p, p') reaction can excite spin-M1 states (states populated by spin-M1 transitions) with T = 2 and 3 that are analogous to the T = 2 and 3 GT states, respectively. By comparing the spectra from these two reactions, a T value of 2 is suggested for several GT states in the E-x = 11.5-13.7 MeV region. (iii) It has been suggested that the T = 2, J(pi) = 0(+) double isobaric analog state (DIAS) at 9.338 MeV in the T-z = 0 nucleus Ti-44 forms an isospin-mixed doublet with a subsidiary 0(+) state at 9.298 MeV. Since no corresponding state was found in the T-z = +1 nucleus Sc-44, we suggest T = 0 for the subsidiary state. |
| Address |
[Fujita, Y.; Fujita, H.] Osaka Univ, Dept Phys, Toyonaka, Osaka 5600043, Japan, Email: fujita@rcnp.osaka-u.ac.jp |
| Corporate Author |
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Thesis |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0556-2813 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000321839100001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1495 |
| Permanent link to this record |
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| Author |
Fujita, Y. et al; Algora, A.; Estevez-Aguado, E; Molina, F; Rubio, B. |
| Title |
High-resolution study of Gamow-Teller excitations in the Ca-42(He-3,t)Sc-42 reaction and the observation of a “low-energy super-Gamow-Teller state” |
Type |
Journal Article |
| Year |
2015 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
91 |
Issue |
6 |
Pages |
064316 - 15pp |
| Keywords |
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| Abstract |
To study the Gamow-Teller (GT) transitions from the T-z = +1 nucleus Ca-42 to the T-z = 0 nucleus Sc-42, where T-z is the z component of isospin T, we performed a (p, n)-type (He-3, t) charge-exchange reaction at 140 MeV/nucleon and scattering angles around 0 degrees. With an energy resolution of 29 keV, states excited by GT transitions (GT states) could be studied accurately. The reduced GT transition strengths B(GT) were derived up to the excitation energy of 13 MeV, assuming the proportionality between the cross sections at 0 degrees and B(GT) values. The main part of the observed GT transition strength is concentrated in the lowest 0.611-MeV, J(pi) = 1(+) GT state. All the other states at higher energies are weakly excited. Shell-model calculations could reproduce the gross feature of the experimental B(GT) distribution, and random-phase-approximation calculations including an attractive isoscalar interaction showed that the 0.611-MeV state has a collective nature. It was found that this state has all of the properties of a “low-energy super-Gamow-Teller state.” It is expected that low-lying J(pi) = 1(+) GT states have T = 0 in the T-z = 0 nucleus Sc-42. However, T = 1 states are situated in a higher energy region. Assuming an isospin-analogous structure in A = 42 isobars, analogous T = 1, 1(+) states are also expected in Ca-42. Comparing the Ca-42(He-3, t)Sc-42 and Ca-42(p, p') spectra measured at 0 degrees, candidates for T = 1 GT states could be found in the 10-12-MeV region of Sc-42. They were all weakly excited. The mass dependence of the GT strength distributions in Sc isotopes is also discussed. |
| Address |
[Fujita, Y.; Fujita, H.; Adachi, T.; Susoy, G.; Hatanaka, K.; Hirota, K.; Ishikawa, D.; Matsubara, H.; Okamura, H.; Ong, H. J.; Suzuki, T.; Tamii, A.; Zenihiro, J.] Osaka Univ, Res Ctr Nucl Phys, Ibaraki, Osaka 5670047, Japan, Email: fujita@rcnp.osaka-u.ac.jp |
| Corporate Author |
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Thesis |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0556-2813 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000356928700001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
2283 |
| Permanent link to this record |
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| Author |
Ganioglu, E. et al; Algora, A.; Estevez-Aguado, E.; Molina, F.; Rubio, B. |
| Title |
High-resolution study of Gamow-Teller transitions in the Ti-47(He-3, t)V-47 reaction |
Type |
Journal Article |
| Year |
2013 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
87 |
Issue |
1 |
Pages |
014321 - 12pp |
| Keywords |
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| Abstract |
Given the importance of Gamow-Teller (GT) transitions in nuclear structure and astrophysical nuclear processes, we have studied T-z = +3/2 -> +1/2, GT transitions starting from the Ti-47 nucleus in the (He-3, t) charge-exchange reaction at 0 degrees and at an intermediate incident energy of 140 MeV/nucleon. The experiments were carried out at the Research Center for Nuclear Physics (RCNP), Osaka, using the high-resolution facility with a high-dispersion beam line and the Grand-Raiden spectrometer. With an energy resolution of 20 keV, individual GT transitions were observed and GT strength was derived for each state populated up to an excitation energy (E-x) of 12.5 MeV. The GT strength was widely distributed from low excitation energy up to 12.5 MeV, where we had to stop the analysis because of the high level density. The distribution of the GT strengths was compared with the results of shell model calculations using the GXPF1 interaction. The calculations could reproduce the experimental GT distributions well. The GT transitions from the ground state of Ti-47 and the M1 transitions from the isobaric analog state in V-47 to the same low-lying states in V-47 are analogous. It was found that the ratios of GT transition strengths to the ground state, the 0.088-MeV state, and the 0.146-MeV state are similar to the ratios of the strengths of the analogous M1 transitions from the isobaric analog state (IAS) to these states. The measured distribution of the GT strengths was also compared with those starting from the T-z = +3/2 nucleus K-41 to the T-z = +1/2 nucleus Ca-41. |
| Address |
[Ganioglu, E.; Susoy, G.] Istanbul Univ, Dept Phys, TR-34134 Istanbul, Turkey, Email: ganioglu@istanbul.edu.tr; |
| Corporate Author |
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Thesis |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0556-2813 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000313548700005 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1308 |
| Permanent link to this record |
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| Author |
Ganioglu, E. et al; Rubio, B.; Algora, A.; Estevez-Aguado, E.; Molina, F. |
| Title |
High-resolution study of Gamow-Teller transitions in the Ti-48(He-3,t)V-48 reaction |
Type |
Journal Article |
| Year |
2016 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
93 |
Issue |
6 |
Pages |
064326 - 10pp |
| Keywords |
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| Abstract |
In this work we have studied T-z = +2 -> +1, Gamow-Teller (GT) transitions in the Ti-48(He-3, t)V-48 chargeexchange reaction at 140 MeV/nucleon and 0 degrees at the Research Center for Nuclear Physics, Osaka. From the high-resolution facility, consisting of a high-dispersion beamline and the Grand Raiden spectrometer, the spectrum had an energy resolution of 21 keV, among the best achieved. Individual GT transitions were observed and GT strength was derived for each state populated up to an excitation energy of 12 MeV. The total sum of the B(GT) strength observed in discrete states was 4.0, which is 33% of the sum-rule-limit value of 12. The results were compared with the results of shell-model calculations carried out with the GXPF1J interaction. The measured B(GT) distribution was also compared with that obtained in the (He-3, t) charge-exchange reaction on Ti-47. On the assumption of isospin symmetry the beta spectrum of the T-z = -2 nucleus Fe-48 was deduced from the observed spectrum in the Ti-48(He-3, t)V-48 reaction and this predicted spectrum was compared with the measured one. |
| Address |
[Ganioglu, E.; Susoy, G.] Istanbul Univ, Dept Phys, TR-34134 Istanbul, Turkey, Email: ganioglu@istanbul.edu.tr |
| Corporate Author |
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Thesis |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2469-9985 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000378818000001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
2740 |
| Permanent link to this record |
