Near-threshold diffractive psi-meson photoproduction from the proton

Photoproduction of a phi meson on protons was studied by means of linearly polarized photons at forward angles in the low-energy region from threshold to Egamma = 2.37 GeV. The differential cross sections at t = -|t|min do not increase smoothly as Egamma increases but show a local maximum at around 2.0 GeV. The angular distributions demonstrate that phi mesons are photoproduced predominantly by helicity-conserving processes, and the local maximum is not likely due to unnatural-parity processes.     

Soft dipole resonance in the neutron-skin nucleus 6He

We consider a billiard model of a self-bound, interacting three-body system in two spatial dimensions. Numerical studies show that the classical dynamics is chaotic. The corresponding quantum system displays spectral fluctuations that exhibit small deviations from random matrix theory predictions. These can be understood in terms of a new type of scarring caused by a one-parameter family of orbits inside the collinear manifold.     

Generation of 0.1 THz coherent synchrotron radiation with compact S-band linac at AIST

The 0.1 THz coherent synchrotron radiation (CSR) was successfully generated in the 90° bending magnet of the compact S-band linac with the achromatic arc section using the ultra-short electron bunch which has the energy of 40 MeV, the bunch charge of about 1nc and the bunch length less than 1 ps (rms). The electron bunch compression of 1 nC electron bunch was achieved less than 1 ps (rms) by controlling the Q-magnets in the achromatic arc section as the bunch length was measured by the rms bunch length monitor.     

Measurement of coherent terahertz radiation for time-domain spectroscopy and imaging

A high-power terahertz (THz) source for THz time-domain spectroscopy (THz-TDS) and THz imaging has been developed based on an S-band compact electron linac at the National Institute of Advanced Industrial Science and Technology (AIST). A THz pulse was generated as coherent synchrotron radiation (CSR) from an ultra-short electron bunch and expected to have peak power of kW-order with frequency range of 0.1–2 THz. The electro-optic (EO) sampling method with a ZnTe crystal for the THz pulse measurement has been prepared for THz-TDS system. The timing measurement between the THz pulse and a probe laser was carried out. A preliminary experiment of THz transmission imaging of an integrated circuit (IC) card has been successfully demonstrated using the THz CSR pulse and a W-band rf detector. The imaging result was experimentally compared with a result of X-ray imaging. It is confirmed that its intensity and stability are enough to perform for the THz applications.     

Synthesis of membranes having a saccharide side chain and their optical resolution properties for d-/l- glucose mixtures

The objective of the present investigation is to synthesize new polymeric membranes having a saccharide in the side chain and to clarify the specific affinity of the saccharide chains. During this study chloromethylated polysulfone (CM-PSF), poly(chloromethylated styrene) (P-CM-St), poly(methyl methacrylate) (PMMA), and chlororethylated poly(γ -methyl L-glutamate) (CE-PMLG) as synthetic polymers along with an equal mixture of α-D-2-deoxy-2-aminoglucopyranosyl-(1'→6) -D-sorbitol and mannitol (AGP) as saccharides were used. PMMA+AGP and CE-PMLG+AGP membranes showed the highest permeability of D-glucose in sugars (molecular weight = 180.16), although the CM-PSP+AGP and P-CM-St+AGP membranes showed less permeability. The reason for the high permeability of D-glucose is the high partition coefficient of D-glucose, which may come from an interaction between the AGP terminating D-glucose structure and D-glucose as the solute. The optical resolution could be done by the difference between the D- and L-glucose permeation rates from an equimolar mixture of D-glucose and L-glucose.     

Collective and single-particle states at high excitation energy

Damping of high-lying single-particle states was investigated by the study of decay by proton emission from high-lying states in ⁹¹Nb, populated by the ⁹⁰Zr(α, t) reaction at E_α=180 MeV. In addition to decay to the ground state of ⁹⁰Zr, semi-direct decay was observed to the low-lying (2⁺/5^? and 3^?) phonon states, confirming the conclusion from other experiments that phonon states play an important role in the damping process of the single-particle states. Furthermore, the population and decay of isobaric analogue states of ⁹¹Zr, which are located at an excitation energy of about 10–12 MeV in ⁹¹Nb, has been studied in the same reaction.     

Experiment at SPring-8

The GeV photon beam at SPring-8 is produced by backward-Compton scattering of laser photons from 8 GeV electrons. The maximum energy of the photon will be above 3 GeV, and the beam intensity will be 10⁷ photons/sec. Polarization of the photon beam will be 100 % at the maximum energy with fully polarized laser photons. We report the outline of the quark nuclear physics project with this high-quality high-intensity beam.