Program - Brookhaven National Laboratory

y the screening potential predicted by atomic physics. We have measured the reaction rates of the 6 Li+d
and 7 Li+p reactions in the different environment: the target Li is in liquid phase. The measurements
were performed for the bombarded energies from 25 to 70 keV with the experimental setup described in
[2]. In this work we discuss the Sbare(E) by analyzing our experimental data together with those so far
reported. It is known that the measured S(E) factor is modified as S(E) = f(E,Us)Sbare(E), where f(E,Us)
is the enhancement factor (approximately = exp(πηUs/E)) and Us is the screening energy. In order to
determine the Sbare(E) of the 6 Li+d and 7 Li+p, we set the policy for the analysis; the Sbare(E) depends
only on the nuclear reaction but Us depends on the environment. In the analyses, therefore, we introduced
Sbare independently for the 6 Li+d and 7 Li+p reaction and Us independently for the difference of target
conditions (the Us should be same for both reactions measured in the same environment). By searching
for the parameters in Sbare and Us so as to reproduce all the experimental S(E), we determined Sbare for
both nuclear reactions and Us for both target conditions simultaneously. The astrophysical Sbare(0) values
are 19.7 (0.5) MeVb and 62.3 (1.5) keVb for the 6 Li+d and 7 Li+p reaction, respectively. The Us values
are 220 (40) eV for the atom target and 436 (50) eV for the liquid Li. It should be noticed that the Us for
the atom target is consistent with the one predicted with adiabatic approximation.
[1] S. Engstler et al., Z. Phys. A342 (1992) 471. [2] K.H. Fang et al., J. Phys. Soc. Jpn. 80 (2011) 084201.
Session OD Nuclear Structure and Decay
Thursday March 7, 2013
Room: Empire West at 1:30 PM
OD 1 1:30 PM
Determination of absolute Gamow Teller transition probabilities in exotic fp-shell nuclei
B. Rubio, S.E.A. Orrigo, F. Molina, J. Agramunt, A. Algora, C. Domingo-Pardo, J.L. Tain, IFIC,
CSIC-Universidad de Valencia, E-46071 Valencia, Spain. Y. Fujita, Department of Physics, Osaka
University, Toyonaka, Osaka 560-0043, Japan. K. Kucuk, R. B. Cakirli, E. Ganioglu, Y. Oktem, G.
Sussoy, Department of Physics, Istanbul University, Istanbul, Turkey. P. Acher, B. Blank, M. Gerbaux, J.
Giovinazzo, S. Grevy, T. Kurtukian-Nieto, CENBG, Univ. Bordeaux 1, UMR 5797 CNRS/IN2P3, BP
120, F-33175 Gradignan, France. W. Gelletly, Zs. Podolyak, Department of Physics, University of
Surrey, Guilford GU2 7XH, Surrey, UK. T. Adachi, H. Fujita, A. Tamii, RCNP, Osaka University,
Ibaraki, Osaka 567-0047, Japan. J.C. Thomas, L. Caceres, R. Raabe, GANIL, BP 55027, F-14076 Caen,
France. P. Boutacjkov, M. Gorska, J. Grebosz, R. Kumar, S. Pietri, GSI, D-64291 Darmstadt, Germany.
J. Benlliure, A.I Morales, M. Gascon, Univ. Santiago de Compostela, E-15782 Santiago de Compostela,
Spain.
Weak interaction processes play an essential role in many astrophysical scenarios. In many cases their
description involves a knowledge of the properties of many nuclei that have to be theoretically modeled
since experimental information is not available. It is essential that sufficient experimental data are available
to test, constrain and guide the theoretical models. This paper concerns the determination of the absolute
value of the Gamow-Teller transition strength B(GT) in fp-shell nuclei. These nuclei are important e.g. in
neutrino induced reactions at the violent core-collapse stage of type II supernovae. Experimental B(GT)
values can be obtained from charge-exchange (CE) reactions on stable nuclei or from beta decay since
they involve the same operator. These two studies are to a large extent complementary, each having
their own advantages and disadvantages. Assuming isospin symmetry one can combine the results from
both types of study on mirror nuclei to determine absolute B(GT) values. This method, the so-called
‘merged analysis’ is very powerful since it allows B(GT) determinations for GT transitions starting from
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