Speaker
Prof.
I. Tanihata
(School of Physics and Nuclear Energy Engineering and IRCNPC, Beihang University, Beijing 100191, China and RCNP, Osaka University, Ibaraki, Osaka 567-0047, Japan)
Description
The Gamow-Teller transition (G-T) strengths are important for understanding nucleosynthesis in stars. The transition strength not only from a ground state but also from an excited state become important in some cases. Charge exchange reactions provide information of G-T strength even for transitions to excited states. However such studies had been done only at around stable nuclei. Here we show the first measurement of charge exchange (p,n) reaction on C isotopes from A=12 to 19 and demonstrate the feasibility of such experiments.
In the present experiment, production cross sections of nitrogen isotopes from high-energy (~950 MeV per nucleon) carbon isotopes on hydrogen have been measured. The fragment separator FRS at GSI was used to deliver C-isotope beams. Since the production of nitrogen is mostly due to charge-exchange (Cex) reactions below the proton separation energies, the present data reveal Gamow–Teller and/or Fermi transition strength at low excitation energies for neutron-rich carbon isotopes. The windows of a Cex reaction below the proton emission threshold and window of the beta-decay are very close with each other for neutron rich nuclei because of the small neutron separation energy.
Comparisons of transition strength obtained by two methods were made for C isotopes and consistent results were obtained for nuclei of which beta-strength are known. In light nuclei most of the transition is allowed and thus no complications due to forbidden transition is seen. The Cex cross section increases for more neutron-rich C isotopes indicating the increase of sum of the beta strength within the window.
Since the two windows are almost same for nuclei along the r-process path, studies of charge exchange reactions of r-process nuclei would provide information on the total strength of beta decay complementary with the half-life measurement in which decay strength are weighted by the decay energy of each decay channel.
A simultaneous measurement of the neutrons and fragments is expected to give us more detailed information. Perspective and future experiments will be discussed in addition.
Primary author
Prof.
I. Tanihata
(School of Physics and Nuclear Energy Engineering and IRCNPC, Beihang University, Beijing 100191, China and RCNP, Osaka University, Ibaraki, Osaka 567-0047, Japan)
Co-authors
Dr
A. Estrade
(Saint Mary’s University, Halifax, NS B3H 3C3, Canada and GSI Helmholtz Center for Heavy-Ion Research, 64291 Darmstadt, Germany)
Dr
A. Evdokimov
(GSI Helmholtz Center for Heavy-Ion Research, 64291 Darmstadt, Germany)
Dr
A. Prochazka
(GSI Helmholtz Center for Heavy-Ion Research, 64291 Darmstadt, Germany)
Dr
B. Sitar
(Comenius University, Bratislava, Slovakia)
Dr
B.-H. Sun
(School of Physics and Nuclear Energy Engineering and IRCNPC, Beihang University, Beijing 100191, China)
Dr
C. Nociforo
(GSI Helmholtz Center for Heavy-Ion Research, 64291 Darmstadt, Germany)
Prof.
C. Scheidenberger
(GSI Helmholtz Center for Heavy-Ion Research, 64291 Darmstadt, Germany and Justus Liebig-Universitäte Giessen, II Physikalsches Institut,35390 Giessen , Gemany)
Dr
D. Cortina-Gil
(Universidad de Santiago de Compostela, Santiago de Compostela, Spain)
Dr
F. Ameil
(GSI Helmholtz Center for Heavy-Ion Research, 64291 Darmstadt, Germany)
Dr
F. Farinon
(GSI Helmholtz Center for Heavy-Ion Research, 64291 Darmstadt, Germany)
Prof.
H. Geissel
(GSI Helmholtz Center for Heavy-Ion Research, 64291 Darmstadt, Germany and Justus Liebig-Universitäte Giessen, II Physikalsches Institut,35390 Giessen , Gemany)
Dr
H. Ong
(RCNP, Osaka University, Ibaraki, Osaka 567-0047, Japan)
Dr
H. Weick
(GSI Helmholtz Center for Heavy-Ion Research, 64291 Darmstadt, Germany)
Dr
I. Dillmann
(GSI Helmholtz Center for Heavy-Ion Research, 64291 Darmstadt, Germany and Justus Liebig-Universitäte Giessen, II Physikalsches Institut,35390 Giessen , Gemany)
Dr
I. Mukha
(GSI Helmholtz Center for Heavy-Ion Research, 64291 Darmstadt, Germany)
Dr
J. Atkinson
(Saint Mary’s University, Halifax, NS B3H 3C3, Canada)
Dr
J. Kurcewicz
(GSI Helmholtz Center for Heavy-Ion Research, 64291 Darmstadt, Germany)
Dr
J. Tanaka
(RCNP, Osaka University, Ibaraki, Osaka 567-0047, Japan)
Dr
J. Vargas
(Universidad de Santiago de Compostela, Santiago de Compostela, Spain)
Dr
J. Winfield
(GSI Helmholtz Center for Heavy-Ion Research, 64291 Darmstadt, Germany)
Dr
M. Marta
(GSI Helmholtz Center for Heavy-Ion Research, 64291 Darmstadt, Germany)
Dr
M. Takechi
(GSI Helmholtz Center for Heavy-Ion Research, 64291 Darmstadt, Germany)
Dr
P. Strmen
(Comenius University, Bratislava, Slovakia)
Dr
R. Janik
(Comenius University, Bratislava, Slovakia)
Prof.
R. Kanungo
(Saint Mary’s University, Halifax, NS B3H 3C3, Canada)
Dr
R. Knoebel
(GSI Helmholtz Center for Heavy-Ion Research, 64291 Darmstadt, Germany)
Dr
S. Pietri
(GSI Helmholtz Center for Heavy-Ion Research, 64291 Darmstadt, Germany)
Dr
S. Terashima
(School of Physics and Nuclear Energy Engineering and IRCNPC, Beihang University, Beijing 100191, China)
Dr
X.-D. Tang
(Institute of Modern Physics,Chinese Academy of Science, Lanzhou, 730000 China)
Dr
Y. Ayyad
(RCNP, Osaka University, Ibaraki, Osaka 567-0047, Japan)
Dr
Yu. Litvinov
(GSI Helmholtz Center for Heavy-Ion Research, 64291 Darmstadt, Germany)