ELFT HÍRADÓ

[Máté Zoltán <mate AT atomki.mta.hu>]

Az MTA Atommagkutató Intézetének előadótermében
(Debrecen, Bem tér 18/c. 12. ép. III. em.)
2013. november 14-én, csütörtökön 11:00-kor
 
 
                    Tomohiro UESAKA
    (RIKEN Nishina Center for Accelerator-Based Science)
                    
      Shed Light of Spin Polarization on Exotic Nuclei   
 
 
 címmel előadást tart.
 
 Az előadás előtt 10:30-tól tea, vendégeket szívesen látunk.
 
 
                                            Máté Zoltán


Abstract:
Recent experimental and theoretical studies have revealed that spin degrees 
of freedom play a vital
role in exotic nuclei. Tensor force effects on the evolution of shell and 
possible occurrence of p-n
pairing in the proton-rich region are good examples of manifestations of spin 
degrees of freedom.
In exploring the spin effects in exotic nuclei, scattering with polarized 
protons should be a
powerful tool. We have constructed a novel polarized proton solid target[1] 
aiming to shed light of
polarization on the physics of exotic nuclei. A distinguished feature of the 
target system is that it
works under a low magnetic field of 0.1 T and a high temperature of 100 K, 
which exhibits a
striking contrast to standard DNP targets working in extreme conditions of 
several Tesla and sub-
Kelvin.
The polarized proton target was applied, for the first time, to measurement 
of vector analyzing
power in the proton elastic scattering of neutron-rich 6,8He nuclei at 71 
MeV/nucleon at RIPS,
RIKEN[2, 3]. The data of vector analyzing power indicate that 1) spin-orbit 
potentials in neutronrich
6,8He nuclei are considerably shallower that those of stable nuclei and 2) 
the α clusters in 6,8He
are major origins of the spin-orbit potentials. In particular, it is 
indicated that the α-cluster
distribution is a possible key for understanding spin-orbit coupling in those 
nuclei. At RI Beam
Factory, the polarized target has been applied to hole-state spectroscopy via 
the (p,2p) knockout
reaction from unstable oxygen isotopes.
In the seminar, I will begin with a general overview of spin physic of exotic 
nuclei and of a
polarized proton target system developed at RIKEN. Subsequently, the results 
from the proton
elastic scattering experiments and the (p,2p) knockout experiments will be 
presented.
[1] T. Wakui et al. , Nucl. Instrum. Methods Phys. Res. A 550 (2005) 521.
A. Obertelli and T. Uesaka, Eur. Phys. J. 47 (2011) 105.
[2] T. Uesaka, S. Sakaguchi et al., Phys. Rev. C 82 (2010) 021602(R).
S. Sakaguchi et al., Phys. Rev. C 84 (2011) 024604.
[3] S. Sakaguchi et al., Phys. Rev. C 87 (2013) 021601(R).