Ⅰ. HIGHLIGHTS OF THE YEARRIKEN Accel. Prog. Rep. 49 (2016)

Deuteron Analyzing Powers for d–p elastic scattering at 190
MeV/nucleon and three–nucleon force eﬀects
K. Sekiguchi,¤1¤2 T. Akieda,¤1 Y. Wada,¤1 D. Eto,¤1 A. Watanabe,¤1 H. Kon,¤1 N. Sakamoto,¤2H. Sakai,¤2 M. Sasano,¤2 H. Suzuki,¤2 T. Uesaka,¤2 Y. Yanagisawa,¤2 M. Dozono,¤3 Y. Kubota,¤3 K. Yako,¤3
Y. Maeda,¤4 S. Kawakami,¤4 T. Yamamoto,¤4 S. Sakaguchi,¤5 T. Wakasa,¤5 J. Yasuda,¤5 A. Ohkura,¤5Y. Shindo,¤5 M. Tabata,¤5 E. Milman,¤2¤6 and S. Chebotaryov¤2¤6Study of three-nucleon forces (3NFs) is essentially
important in clarifying nuclear phenomena, e.g. discrete states of nuclei and equation of state of nuclear
matter. Nucleon–deuteron (N d) scattering, for which
a rigorous formulation in terms of Faddeev equations
exists and exact solutions of these equations for any
dynamical input can be obtained, oﬀers a good opportunity for the dynamical aspects of 3NFs, such asmomentum, spin and/or iso-spin dependences. With
the aim of clarifying properties of the 3NFs the studyof energy dependent deuteron–proton (d–p) scatteringwith polarized deuteron beams at intermediate energies (E ∼ 200 MeV/nucleon(MeV/N)) are in progress
at RIBF. Here we report a measurement of all thedeuteron analyzing powers (iT11 , T20 , T21 , and T22 )in d–p elastic scattering at 190 MeV/N performed inMay 2015.
A schematic diagram of the experimental setup isprovided in Ref.1) . Vector- and tensor- polarized
deuteron beams were accelerated by the injector cyclotrons AVF and RRC up to 70 MeV/N; subsequently,
they were accelerated up to 190 MeV/N by the SRC.
The measurement of the d–p elastic scattering wasperformed using a detector system, BigDpol, which
was installed at the extraction beam line of the SRC.
Polyethylene (CH2 ) with a thickness of 330 mg/cm2
was used as hydrogen target. In BigDpol, four pairsof plastic scintillators coupled with photo-multipliertubes were placed symmetrically in the directions ofazimuthal angles to the left, right, up and down. Scattered deuterons and recoil protons were detected in
the kinematical coincidence condition by each pair ofthe detectors. The measured angular range is 39◦ –165◦ in the center-of-mass system. In the experiment,
the deuteron beams were stopped in the Faraday cup,
which was installed at the focal plane F0 of the BigRIPS spectrometer. The beam polarizations weremonitored continuously with a beam line polarimeter
Dpol prior to the acceleration by the SRC using thereaction of elastic d–p scattering at 70 MeV/nucleon.
The analyzing powers for this reaction have been calibrated in the previous measurement by using the12C(d, α)10 B∗ [2+ ] reaction2) . In the measurement typ∗1
∗2
∗3
∗4
∗5
∗6

ical values of the beam polarizations were 80% of thetheoretical maximum values.
Preliminary results are shown with open circles inFig. 1. Only the statistical uncertainties are shown.
The data are compared with the Faddeev calculations
with (without) Tucson–Melbourne’99 3NF3) based on
the modern NN potentials, namely CDBonn4) , AV185) ,Nijmegen I and II6) . The solid lines are the calculations with the Urbana IX 3NF7) based on the AV18
potential. Generally data for the backward angles
θc.m. ≳ 120◦ are well explained by the calculations
with the 3NFs except for T20 .
Detailed analysis is now in progress. Discussions
on the energy-dependence of the deuteron analyzing
powers for d–p elastic scattering at 70–300 MeV/N will
be performed.

Fig. 1. Preliminary results of the vector and tensor analyzing powers for the d-p elastic scattering at 190 MeV/N.

References
1) K. Sekiguchi et al., Phys. Rev. C 89, 064007 (2014).
2) K. Suda et al., Nucl. Instrum. Methods Phys. Res. A.
572, 745 (2007).
3) S. A. Coon, H. K. Han, Few Body Syst. 30, 131 (2001).
4) R. Machleidt, Phys. Rev. C 63, 024001 (2001).
5) R. B. Wiringa et al., Phys. Rev. C 51, 38 (1995).
6) V. G. J. Stoks et al., Phys. Rev. C 49, 2950 (1994).
7) B. S. Pudliner et al., Phys. Rev. C56, 1720 (1997).

Department of Physics, Tohoku University
RIKEN Nishina Center
CNS, University of Tokyo
Faculty of Engineering, University of Miyazaki
Department of Physics, Kyushu University
Department of Physics, Kyungpook National University-5-