RIKEN Accel. Prog. Rep. 50 (2017)

Ⅱ-1. Nuclear Physics

Deuteron analyzing powers for d-p elastic scattering
at 186.6 MeV/nucleon∗1∗2K.
K. Sekiguchi,Sekiguchi,∗1,∗2
T. Akieda,∗1 Y. Wada,∗1 D. Eto,∗1 A. Watanabe,∗1 H. Kon,∗1 N. Sakamoto,∗2
∗2
∗2
∗2
∗2
∗2
∗2
∗2
∗3
∗3
H. Sakai,
Sakai, M.
M. Sasano,
Sasano, H.
H. Suzuki,Suzuki,∗2T.Uesaka,
Uesaka,∗2Y.Yanagisawa,
Yanagisawa,∗2M. Dozono,Dozono,∗3
Y. Kubota,
Kubota,∗3K.Yako,
Yako∗3H.
T.
Y.
M.
Y.
K.
∗4
∗4
∗4
∗5
∗5
∗4
∗4
∗4
∗5
Y. Maeda,Maeda, S.
S. Kawakami,Kawakami, T.
T. Yamamoto,Yamamoto, S.
S. Sakaguchi,
Sakaguchi, T.
T. Wakasa,Wakasa, J. Yasuda, A. Ohkura,∗5Y.
∗5
∗5
∗2∗6
∗2∗6
Y. Shindo,
Shindo,∗5 M.
M.Tabata,
Tabata,∗5 E.
E. Milman,
Milman,∗2,∗6 andand S.
S. Chebotaryov
Chebotaryov∗2,∗6Y.

tistical uncertainties are shown. It is interesting to see
the potential of χEFT to describe deuteron analyzing
powers for d–p elastic scattering. In Fig. 1, the data
are compared with the calculations based on the χEFT
N4LO NN potentials.5) Gnerally good agreements areobtained for the vector analyzing power iT11 , whilelarge discrepancies are found for the tensor analyzing power T22 . In order to examine how χEFT 3NFs
describe the data, theoretical treatments are now inprogress6) .

The study of three nucleon forces (3NFs) is essentially important for clarifying nuclear phenomena.
3NFs arise naturally in the standard meson exchangepicture1) as well as in the framework of the chiraleﬀective ﬁeld theory (χEFT) which has a link toQCD.2,3) Three-nucleon scattering at intermediate energies (E/A ∼ 200 MeV) is one attractive approach toinvestigate the dynamical aspects of 3NFs, such as momentum and/or spin dependences. Here we report themeasurement of all deuteron analyzing powers (iT11 ,T20 , T21 , and T22 ) in deuteron–proton (d–p) elastic
scattering at 186.6 MeV/nucleon (MeV/N) performed
in May 2015.
A schematic diagram of the experimental setup has
been provided in Ref. (4). 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 186.6 MeV/N by SRC. The
measurement for d–p elastic scattering was performed
using a detector system, BigDpol, which was installedat the extraction beam line of SRC. Polyethylene witha thickness of 330 mg/cm2 was used as the hydrogentarget. In BigDpol, four pairs of plastic scintillators
coupled with photo-multiplier tubes were placed symmetrically in the directions of azimuthal angles to theleft, right, up and down. Scattered deuterons and recoil protons were detected in the kinematical coincidence condition by each pair of detectors. The angles(θc.m. ) measured in the center-of-mass system are in
the range of 39◦ –165◦ . In the experiment, the deuteronbeams were stopped in a Faraday cup installed at thefocal plane F0 of the BigRIPS spectrometer. The
beam polarizations were monitored continuously witha beam line polarimeter Dpol prior to acceleration by
SRC using the reaction of elastic d–p scattering at 70
MeV/N. At RIBF, single-turn extractions were available for all the cyclotrons used for the experiments.
Therefore, depolarizations were expected to be small
during beam acceleration. In the measurement typical values of the beam polarizations were 80% of thetheoretical maximum values.
Results of the deuteron analyzing powers iT11 andT22 are shown with solid circles in Fig. 1. Only the sta∗1
∗2
∗3
∗4
∗5
∗6Fig. 1. Results of deuteron analyzing powers iT11 and T22for d-p elastic scattering at 186.6 MeV/N.

References1) J. Fujita, H. Miyazawa, Prog. Theor. Phys. 17, 360(1957).
2) U. van Kolck, Phys. Rev. C 49, 2932 (1994).
3) E. Epelbaum, H.-W. Hammer, U.-G. Meißner, Rev.
Mod. Phys. 81, 1773 (2009).
4) K. Sekiguchi et al., Phys. Rev. C 89, 064007 (2014).
5) S. Binder et al., Phys. Rev. C 93, 044002 (2016).
6) E. Epelbaum, private communications.

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- 62 -