Characterization of unique subregions of the caudal lateral striatum : in their conserved expression patterns of dopamine receptors D1 and D2 in rodents and primates

It was generally accepted that dopamine receptors D1 (D1R)- and D2 (D2R)-expressing neurons are homogeneously and randomly distributed throughout the striatum. However, in reporter transgenic mice, the specific subregions of the caudal lateral striatum have been reported: the D1R-poor zone, in which D2R-expressing neurons are predominant, and the D2R-poor zone, in which D1R-expressing neurons are predominant. The present study demonstrated the presence of these distinct subregions not only in rodents but also in marmosets using endogenous dopamine receptors. We also showed that direct pathway medium spiny neurons in these distinct subregions preferentially project to parvalbumin-positive GABAergic neurons in the dorsal part of the substantia nigra pars lateralis.application/pdfdoctoral thesi

Measurements of exclusive B_s^0 decays at the Y(5S) resonance

Several exclusive $B_s^0$ decays are studied using a 1.86 fb-1 data sample collected at the Y(5S) resonance with the Belle detector at the KEKB asymmetric energy e^+ e^- collider. In the $B_s^0 \to D_s^- \pi^+$ decay mode we find 10 $B_s^0$ candidates and measure the corresponding branching fraction. Combining the B_s^0 -> D_s^{(*)-} \pi^+, B_s^0 -> D_s^{(*)-} \rho^+, B_s^0 -> J/\psi \phi and B_s^0 -> J/\psi \eta decay modes, a significant $B_s^0$ signal is observed. The ratio \sigma (e^+ e^- -> B_s^* \bar{B}_s^*) / \sigma (e^+ e^- -> B_s^{(*)} \bar{B}_s^{(*)}) = (93^{+7}_{-9} \pm 1)% is obtained at the Y(5S) energy, indicating that $B_s^0$ meson production proceeds predominantly through the creation of $B^*_s \bar{B}^*_s$ pairs. The $B_s^0$ and $B_s^*$ meson masses are measured to be M(B_s^0)=(5370 \pm 1 \pm 3)MeV/c^2 and M(B_s^*)=(5418 \pm 1 \pm 3)MeV/c^2. Upper limits on the B_s^0 -> \gamma \gamma, B_s^0 -> \phi \gamma, B_s^0 -> K^+ K^- and B_s^0 -> D_s^{(*)+} D_s^{(*)-} branching fractions are also reported.Comment: 9 pages, 5 figures, published in Phys. Rev. D76, 012002 (2007

Suzaku Observations of Tycho's Supernova Remnant

Tycho's supernova remnant was observed by the XIS and HXD instruments onboard the Suzaku satellite on 2006 June 26-29 for 92 ks. The spectrum up to 30 keV was well fitted with a two-component model, consisting of a power-law with photon index of 2.7 and a thermal bremsstrahlung model with temperature of 4.7 keV. The former component can alternatively be modeled as synchrotron emission from a population of relativistic electrons with an estimated roll-off energy of around 1 keV. In the XIS spectra, in addition to the prominent Fe K_alpha line (6.445 keV), we observe for the first time significant K_alpha line emission from the trace species Cr and Mn at energies of 5.48 keV and 5.95 keV, respectively. Faint K_beta lines from Ca (4.56 keV) and Fe (7.11 keV) are also seen. The ionization states of Cr and Mn, based on their line centroids, are estimated to be similar to that of Fe K_alpha (Fe XV or XVI).textapplication/pdfjournal articl

Search for Electron Neutrino Appearance in a 250 km Long-Baseline Experiment

journal articl

Measurements of exclusive B^{0}_{s} decays at the γ(5S) resonance

Several exclusive B^{O}_{s} decays are studied using a 1.86 fb^{-1} data sample collected at the Υ(5S) resonance with the Belle detector at the KEKB asymmetric energy e^+e^- collider. In the B^{O}_{s}→D^{-}\{s}π^+ decay mode we find 10 B^{O}_{s} candidates and measure the corresponding branching fraction. Combining the B^{O}_{s}→ D^(*)-_s π^+, B^{O}_{s} → D^(*)-_sρ^+, B^{O}_{s}→ J/Ψφ, and B^{O}_{s}→ J/Ψη decay modes, a significant B^{O}_{S}signal is observed. The ratio σ(e^+e^- → B^{*}_{s}\bar{b}^{*}_{s})/σ(e^+e^- → B^{(*)}_S\bar{B}^{(*)}_s)=(93^{+7}_{-9}±1)% is obtained at the Υ(5S) energy, indicating that B^{O}_{s} meson production proceeds predominantly through the creation of B^{*}_{s}\bar{B}^{*}_S pairs. The B^{O}_{s} and B^{*}_{s} meson masses are measured to be M(B^{O}_{s})=(5370±1±3) MeV/c^2 and M(B^{*}_{s})=(5418±1±3) MeV/c^2. Upper limits on the B^{O}_{s} →γγ, B^{O}_{s} → φγ, B^{O}_{s} → K^+K^-, and B^{O}_{s} → D^{(*)}+_{s}D^{(*)}_s- branching fractions are also reported.journal articl

【活動報告 報告部(個人) ※希望者のみ掲載。五十音順。】長谷川健治

departmental bulletin pape