References - Bogoliubov Laboratory of Theoretical Physics - JINR

higher energies, where the cross sections are much larger[2].
Single-nucleon transfer reactions that probe the degrees of freedom of single particles
have been extensively used to study the structure of stable nuclei. The analysis of such reactions
provides the angular momentum transfer, which gives information on the spin (j)
and parity ( π ) of the final state. The sensitivity of the cross sections to the single-nucleon
components allows for the extraction of spectroscopic factors. The recent indications of
reduced occupancies of single-particle states reveal that reliable measurements of spectroscopic
factors in exotic nuclei are highly desirable [3].
The ( −→ d,p) stripping reaction has long been use as a means of probing the single
particle structure of nuclei. In particular, through distorted wave Born approximation
(DWBA) analysis it has been used to determine the orbital angular momentum and spectroscopic
factors of specific states in the recoil nucleus [1].
In this report, the data on the tensor Ayy, Axx, Axz and vector Ay analyzing powers
for the 12 C( −→ d,p) 13 C ∗ reaction at energy Td = 270 MeV in the angular range from 4 ◦ to
18 ◦ in laboratory system obtained at RIKEN are presented. The experimental results on
analyzing powers at energy Td = 140, 200 and 270 MeV for 12 C( −→ d,p) 13 C ∗ reaction with
excitation of levels of a nucleus 13 C reaction at emission angle Θcm=0 ◦ are also presented.
Experiment
The experiment was performed at RIKEN Accelerator Research Facility (RARF).
Details of the experiment can be found in ref.[4].
N
6000
5000
4000
3000
2000
1000
0
11.08
10.82
10.75
10.46
12.44
12.11
11.95
11.75
9.9
9.5
8.86
8.2 7.67
7.55
6.864 7.49
3.854
3.685
3.089
0.0
0.5 0.505 0.51 0.515 0.52 0.525 0.53 0.535
P, GeV/c
Figure 1: Typical momentum spectra for
12 C( −→ d,p) 13 C ∗ reaction and Θcm=0 ◦ (Td=140
MeV). Peaks corresponding to the 13 C states are labeled
by their excitation energies in MeV.
In this experiment, four spin modes were
used: the mode 0 - unpolarized mode, mode
1 - pure tensor mode, mode 2 - pure vector
mode and mode 3 is mixed mode. The obtained
polarization values were ∼ 75% of
the ideal values. The direction of symmetric
axis of the beam polarization was controlled
with a Wien filter located at the
exit of polarized ion source. The polarized
deuteron beam was accelerated up to
140, 200 and 270 MeV by the combination
of the AVF cyclotron and Ring cyclotron.
The beam polarizations were measured with
D-room polarimeter located at D-room and
Swinger polarimeter placed in the front of
the target.
Scattered particles ( 3 H, 3 He or p) were
momentum analyzed with quadrupole and
dipole magnets (Q-Q-D-Q-D) and detected
with MWDC followed by the three plastic scintillators at the second focal plane. Criteria
used for the identification of the scattered protons from the 12 C( −→ d,p) 13 C ∗ reaction are
the following: particle must be registered in the all three scintillation detectors and it was
selected by the correlation of the energy losses in the 1st and the 2nd and the 1st and the
3rd scintillation detectors; radio frequency signal of the cyclotron was used as a reference
for the time-of-flight measurement.
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