Center for Nuclear Study,

Preface
This is the annual report of the Center for Nuclear Study (CNS), Graduate School of Science,
the University of Tokyo, for the fiscal year 2007 (April 2007 through March 2008). In the CNS,
during this period, a large number of scientific activities in various fields of nuclear physics have been
carried out and a wide variety of fruitful results have been obtained. This report presents a report of
such activities. Some highlights of the report are mentioned here.
The excitation energy and lifetime of the isomeric 0
decay spectra of delayed ¤ -rays from stopped ¢£¡ Be nuclei produced by the projectile fragmentation
of ¢£¥ O at 100 AMeV. Using the branching ratios of the E2 and E0 decays, relatively large reduced
¡ state in ¢£¡ Be were determined by measuring
transition strengths were deduced suggesting deformation of neutron-rich Be ¦¨§�© isotopes around ¢ .
High-spin ������� states in Ti populated by fusion reactions of an RI beam were investigated, where
high-resolution ¤ -ray spectroscopy with precise Doppler-shift corrections was achieved by using the
position-sensitive Ge detector array, CNS GRAPE. To search for superdeformed rotational bands,
high-spin states in A� 100 and A� 30 region were studied by in-beam ¤ -ray spectroscopy in the
collaboration with Kyoto, Kyushu, Tohoku, Osaka, KEK, and JAEA group.
Research programs with CRIB continued in nuclear physics as well as nuclear astrophysics, together
with the AVF upgrade project that enhances the capability of CRIB facility. A non-destructive
beam monitor has been designed, and detailed simulations were made for the central region of the
AVF cyclotron in order to derive the optimum design for high-transmission acceleration of heavy
ions. Several new heavy ion beams of high-intensity and high charge states were developed with the
Hyper ECR source. The first beam was successfully extracted from the super-conducting ECR source
in collaboration with Tsukuba University.
The research programs of nuclear astrophysics include resonance search of light proton-rich nuclei
with proton-rich RI beams from CRIB to investigate the solar model as well as the early stage of
type II supernovae, and a direct measurement of the ¢£¥ F (p, � ) reaction for a nova problem. Elastic
scattering and breakup of ¢�� F+ ¢£¡ C were measured for studying the reaction mechanism of a weakly
bound nuclear system. Test producing RI beams of fp-shell nuclei is also in progress.
The CNS polarized proton target was applied to a measurement of spin-asymmetry in the � - ¥����
elastic scattering. The analyzing power data, together with the � -�
essentially useful for understanding spin-orbit coupling in neutron-rich nuclei.
Considerable progress has been made in SHARAQ project. In summer 2007, all the magnets and
rotating base were installed in E20 experimental area of RI beam factory. Equipped with electricity
of 1 MVA and a cooling water of 1 m� , the SHARAQ magnets are ready to be excited. Detailed fieldmapping
measurement of dipole magnets will be started soon. Development of beam-line and focal
plane detectors has advanced also. Low-pressure multiwire drift chambers developed for beam-line
detectors were tested with an accelerated � -beam with an energy of 8.8 AMeV. They were found to
work well with isobutane gas under as low pressure as several kPa. The design of cathode-readout
drift chambers (CRDC) for the final focal plane detectors has been finalized. According to the design,
two sets of CRDCs will be manufactured in collaboration with GANIL.
The experimental study in the PHENIX experiment at Relativistic Heavy Ion Collider (RHIC) at
Brookhaven National Laboratory has made steady progress toward understanding of the properties of
hot and dense nuclear matter created by colliding gold nuclei at relativistic energies. The CNS group
has been concentrating on the physics analysis utilizing leptons and photons as probes which include
determination of charm and bottom fraction in the non-photonic single electrons, systematics of �����
production in Cu+Cu and Au+Au collisions, deduction of photon yield at low transverse momentum
in p+p and A+A collisions using the virtual-gamma method, and neutral pion production at high
transverse momentum region as a function of azimuthal angle from the reaction plane in Au+Au
collisions. The group has started active participation in the ALICE experiment at Large Hadron
��� data taken in 2005, will be