Evidence for Narrow S=+1 Baryon Resonance in Photo-production from Neutron

The gamma n -> K+ K- n reaction on 12C has been studied by measuring both K+ and K- at forward angles. A sharp baryon resonance peak was observed at 1.54 +- 0.01 GeV with a width smaller than 25 MeV and a Gaussian significance of 4.6 sigma. The strangeness quantum number (S) of the baryon resonance is +1. It can be interpreted as a molecular meson-baryon resonance or alternatively as an exotic 5-quark state (uudd{s_bar}) that decays into a K+ and a neutron. The resonance is consistent with the lowest member of an anti-decuplet of baryons predicted by the chiral soliton model.Comment: 12 pages, 3 encapsulated postscript figure

η\eta photoproduction off the deuteron and low-energy η\eta-nucleon interaction

We study $\eta$ photoproduction off the deuteron ($\gamma d\to\eta pn$) at a special kinematics: $\sim 0.94$ GeV of the photon beam energy and $\sim 0^\circ$ of the scattering angle of the proton. This kinematics is ideal to extract the low-energy $\eta$-nucleon scattering parameters such as $a_{\eta N}$ (scattering length) and $r_{\eta N}$ (effective range) because the $\eta$-nucleon elastic scattering is significantly enhanced. We show that if a ratio $R$, the $\gamma d\to\eta pn$ cross section divided by the $\gamma p\to\eta p$ cross section convoluted with the proton momentum distribution in the deuteron, is measured with 5% error, ${\rm Re}[a_{\eta N}]$ (${\rm Re}[r_{\eta N}]$) can be determined at the precision of $\sim\pm$0.1 fm ($\sim\pm$0.5 fm), significantly narrowing down the currently estimated range of the parameters. The measurement is ongoing at the Research Center for Electron Photon Science (ELPH), Tohoku University.Comment: 4 pages, 5 figures, Contribution to the Proceedings for 8th International Conference on Quarks and Nuclear Physics (QNP2018), November 13-17, 2018, Tsukuba, Japa

Operation of Faddeev-Kernel in Configuration Space

We present a practical method to solve Faddeev three-body equations at energies above three-body breakup threshold as integral equations in coordinate space. This is an extension of previously used method for bound states and scattering states below three-body breakup threshold energy. We show that breakup components in three-body reactions produce long-range effects on Faddeev integral kernels in coordinate space, and propose numerical procedures to treat these effects. Using these techniques, we solve Faddeev equations for neutron-deuteron scattering to compare with benchmark solutions.Comment: 20 pages, 8 figures, to be published in Few-Body System

Visibility and aerosol measurement by diode-laser random-modulation CW lidar

Examples of diode laser (DL) random-modulation continuous wave (RM-CW) lidar measurements are reported. The ability of the measurement of the visibility, vertical aerosol profile, and the cloud ceiling height is demonstrated. Although the data shown here were all measured at night time, the daytime measurement is, of course, possible. For that purpose, accurate control of the laser frequency to the center frequency of a narrow band filter is required. Now a new system with a frequency control is under construction

Spin and spin-spin correlations in chargino pair production at future linear e+e- colliders

A possibility to measure the spin and spin-spin correlations of a chargino pair is investigated in the process electron positron -> chargino_1 anti-chargino_1 -> (neutralino_1 quark anti-quark) (neutralino_1 quark anti-quark) at future linear-collider energies. The total and the differential cross sections are calculated by the GRACE system which allows for the full spin correlation. Experimental sensitivity of the measurements are examined by assuming the limited detector resolution, the initial state radiation and the beam-beam effect (beamstrahlung). It is found that generally the spin-spin correlation can only be measured with a lower sensitivity than the chargino spin itself. The dependence of the correlation measurements on the relevant SUSY parameters can be seen for a light sneutrino case, but the situation becomes worse for a heavier sneutrino.Comment: 23 pages, 7 figures, 6 tables; added reference for section

Axisymmetric polydimethysiloxane microchannels for in vitro hemodynamic studies

The current microdevices used for biomedical research are often manufactured using microelectromechanical systems (MEMS) technology. Although it is possible to fabricate precise and reproducible rectangular microchannels using soft lithography techniques, this kind of geometry may not reflect the actual physiology of the microcirculation. Here, we present a simple method to fabricate circular polydimethysiloxane (PDMS) microchannels aiming to mimic an in vivo microvascular environment and suitable for state-of-the-art microscale flow visualization techniques, such as confocal µPIV/PTV. By using a confocal µPTV system individual red blood cells (RBCs) were successfully tracked trough a 75 µm circular PDMS microchannel. The results show that RBC lateral dispersion increases with the volume fraction of RBCs in the solution, i.e. with the hematocrit