120866230
Z-trigger system with the BELLE Central Drift Chamber
Abstract We describe the design and performance of a fast Z -trigger system with the BELLE Central Drift Chamber. It utilizes z -position information from the axial/stereo wire hits as well as the cathode strip. This system is essential to reduce the false trigger rate from caused by the spent electrons or positrons interacting with the material around the beam pipe. We tested the performance of the system using cosmic rays in a magnetic field of 1.5 T, provided by a superconducting solenoid. The trigger efficiency was 98% for a single track passing through the interaction region. This trigger was effective in rejecting tracks originating from points more than 10 cm away from the interaction point.
120173213
Cathode image readout in the BELLE central drift chamber
Abstract We report on the design and construction of the cathode image readout section of the BELLE detector's central drift chamber. The cathode information is used for measurements of charged particle trajectory coordinates along the beam axis and the charged-track trigger. The performance is evaluated with cosmic rays using the BELLE standard readout electronics and software. The detection efficiency in nominal conditions is found to exceed 98% and the position resolution for normal incidence is about 350 μm, which satisfies the design goals of the BELLE detector.
121863527
Experimental studies of light neutron rich nuclei
Abstract Experimental studies of neutron rich nuclei 8 He, 10 He, 12 Be and 13 Be have been performed using radioactive beams.
124527547
Measurement of the spin and magnetic moment of ²³Al
Author(s) Ozawa, A.; Matsuta, K.; Nagatomo, T.; Mihara, M.; Yamada, K.; Yamaguchi, T.; Momota, S.; Izumikawa, T.; Sumikama, T.; Nakashima, Y.; Fujiwara, H.; Kumashiro, S.; Matsumiya, R.; Ota, M.; Shinojima, D.; Tanaka, H.; Yasuno, T.; Nakajima, S.; Suzuki, T.; Yoshida, K.; Muranaka, K.; Maemura, T.; Chiba, A.; Utsuno, Y.; Fukuda, M.; Tanaka, K.; Tanihata, I.; Nojiri, Y.; Minamisono, T.; Alonso, J.R.; Krebs, G.F.; Symons, T.J.M.
118435601
Vanishing thermal mass in the strongly coupled QCD/QED medium
In this paper we perform a nonperturbative analysis of a thermal quasifermion in thermal QCD/QED by studying its self-energy function through the Dyson-Schwinger equation with the hard-thermal-loop resummed improved ladder kernel. Our analysis reveals several interesting results, some of which may force us to change the image of the thermal quasifermion: (1) The thermal mass of a quasifermion begins to decrease as the coupling gets stronger and finally disappears in the strong coupling region,(2) the imaginary part of the chiral invariant mass function (i.e., the decay width of the quasifermion) persists to have $O(g^2 T \log (1/g))$ behavior. Present results suggest that in the recently produced strongly coupled quark-gluon-plasma, the thermal mass of a quasifermion should vanish. We also briefly comment on evidence of the existence of a massless, or an ultrasoft mode.
106401285
Shape evolution of giant resonances in Nd and Sm isotopes
Giant multipole resonances in Nd and Sm isotopes are studied by employing the quasiparticle-random-phase approximation on the basis of the Skyrme energy-density-functional method. Deformation effects on giant resonances are investigated in these isotopes, which manifest a typical nuclear shape change from spherical to prolate shapes. The peak energy, the broadening, and the deformation splitting of the isoscalar giant monopole (ISGMR) and quadrupole (ISGQR) resonances agree well with measurements. The magnitude of the peak splitting and the fraction of the energy-weighted strength in the lower peak of the ISGMR reflect the nuclear deformation. The experimental data on ISGMR, isoscalar giant dipole (ISGDR), and ISGQR are consistent with the nuclear-matter incompressibility K � 210‐230 MeV and the effective mass m ∗/m � 0.8‐0.9. However, the high-energy octupole resonance (HEOR) in 144 Sm seems to indicate a smaller effective mass, m ∗ /m � 0.7‐0.8. A further precise measurement of HEOR is desired to determine the effective mass.
121806959
Measurements of interaction cross sections for light neutron-rich nuclei at relativistic energies and determination of effective matter radii
Abstract We measured the interaction cross sections ( σ I ) of 10,11B, 12–20C, 14–23N, 16–24O and 18–26F on carbon targets at energies of around 950 A MeV. We then deduced the effective matter radii of the nuclei by a Glauber-model analysis. Based on the assumption of a core plus a valence neutron structure, we applied a Glauber-model analysis for a few-body system adapted for nuclei with an odd neutron number. We also deduced the effective nucleus-matter densities as well as some spectroscopic information for selected nuclei. Evidence for a one-neutron halo structure was found for 22N, 23O and 24F, as well as 19C.