D. Ishikawa

Probing effect of tensor interactions in 16O via (p, d) reaction

Abstract We have measured the 16O(p,u2009d) reaction using 198-, 295- and 392-MeV proton beams to search for a direct evidence on an effect of the tensor interactions in light nucleus. Differential cross sections of the one-neutron transfer reaction populating the ground states and several low-lying excited states in 15O were measured. Comparing the ratios of the cross sections for each excited state to the one for the ground state over a wide range of momentum transfer, we found a marked enhancement of the ratio for the positive-parity state(s). The observation is consistent with large components of high-momentum neutrons in the initial ground-state configurations due to the tensor interactions.

Lo w-Energy Super Gamow-Teller State

Y. Fujita1,2 H. Fujita1 T. Adachi1 C.L. Bai3 A. Algora4,5 G.P.A. Berg6 P. von Brentano7 G. Colo8 M. Csatlos5 J.M. Deaven9 E. Estevez-Aguado4 C. Fransen7 D. De Frenne10 K. Fujita1 E. Ganioglu11 C.J. Guess9 J. Gulyas5 K. Hatanaka1 K. Hirota1 M. Honma12 D. Ishikawa1 E. Jacobs10 A. Krasznahorkay5 H. Matsubara1 K. Matsuyanagi13 R. Meharchand9 F. Molina4 K. Muto14 K. Nakanishi1 A. Negret15 H. Okamura1 H.J. Ong1 T. Otsuka16 N. Pietralla7 G. Perdikakis9 L. Popescu17 B. Rubio4 H. Sagawa13 P. Sarriguren18 C. Scholl7 Y. Shimbara19 Y. Shimizu1 G. Susoy11 T. Suzuki1 Y. Tameshige1 A. Tamii1 J.H. Thies20 M. Uchida1 T. Wakasa1 M. Yosoi1 R.G.T. Zegers1 K.O. Zell7 J. Zenihiro1

Effect of tensor interactions in 16O studied via (p,d) reaction

The differential cross sections of the 16O(p,d) reaction populating the ground state and several low-lying excited states in 15O were measured using 198-, 295- and 392-MeV proton beams at the Research Center for Nuclear Physics (RCNP), Osaka University, to study the effect of the tensor interactions in 16O. Dividing the cross sections for each excited state by the one for the ground state and comparing the ratios over a wide range of momentum transfer, we found a marked enhancement of the ratio for the positive-parity state(s). The observation is consistent with large components of high-momentum neutrons in the ground-state configurations of 16O due possibly to the tensor interactions.

Soft spin-dipole resonances in 40Ca

High resolution experimental data has been obtained for the 40,42,44,48Ca(3He,t)Sc charge exchange reaction at 420 MeV beam energy, which favors the spin-isospin excitations. The measured angular distributions were analyzed for each state separately, and the relative spin dipole strength has been extracted for the first time. The low-lying spin-dipole strength distribution in 40Sc shows some interesting periodic gross feature. It resembles to a soft, damped multi-phonon vibrational band with ω= 1.8 MeV, which might be associated to pairing vibrations around 40Ca.

Measurement of pd breakup cross sections in the off-plane star configurations

We carried out the experiment of the 1H(d,pp)n reactions at Ed = 26 MeV at RCNP and that of the 2H(p, pp)n reactions at Ep = 13 MeV at KUTL. The data of the differential cross sections was measured and compared with the Faddeev calculations based on the various nucleon-nucleon (NN) interactions with/without the Coulomb interactions or the three-nucleon force (3NF). The data is overestimated by the theoretical predictions by less than 10 %. This result is very different from the data at E=9.5 MeV reported from Koln, which showed the large discrepancies between the data and the Faddeev calculations.

Gamow‐Teller Transitions Starting from Tz = +3/2 Nucleus 45Sc

Gamow-Teller (GT) transitions are mediated by the {sigma}{tau} operator. Owing to its simplicity and also its spin-isospin nature, GT transitions play key roles in the studies of nuclear structure as well as astro-nuclear processes. In violent neutrino-induced reactions at the core-collapse stage of type II supernovae, Gamow-Teller (GT) transitions starting from stable as well as unstable pf-shell nuclei play important roles. We study GT transitions starting from {sup 47}Ti in a high-resolution ({sup 3}He,t) charge-exchange reactions at 0 deg. and at an intermediate incident energy of 140 MeV/nucleon at Research Center for Nuclear Physics (RCNP), Osaka. Individual GT transitions up to high excitations were observed. Assuming the isospin symmetry for the strengths of T{sub z} = {+-}3/2{yields}{+-}1/2 analogous GT transitions, we can deduce the detailed strength distribution starting from mirror unstable nucleus {sup 47}Mn.