Baryon resonance production in the π+d\pi+d reaction and search for η\eta-mesic nuclei at J-PARC

A double-scattering reaction $\pi^+ + d\to p + p + \eta$, where an $\eta$ meson is rescattered, may provide new information on the $\eta N\to \eta N$ scattering. An idea to measure this reaction is proposed. Moreover, experimental search for $\eta$-mesic nuclei by the same $(\pi, N)$ reaction is discussed.Comment: Talk given at the Workshop on "Hadron and Nuclear Physics (HNP09)", RCNP, Osaka, Japan, Nov. 16-19, 2009. To appear in the proceeding

Risk evaluation of the groundwater pollution by nitrate-nitrogen leached from farmlands in a middle-sized agricultural watershed

Poster Sessio

Interannual variation in the fine-mode MODIS aerosol optical depth and its relationship to the changes in sulfur dioxide emissions in China between 2000 and 2010

Anthropogenic SO<sub>2</sub> emissions increased alongside economic development in China at a rate of 12.7% yr<sup>−1</sup> from 2000 to 2005. However, under new Chinese government policy, SO<sub>2</sub> emissions declined by 3.9% yr<sup>−1</sup> between 2005 and 2009. Between 2000 and 2010, we found that the variability in the fine-mode (submicron) aerosol optical depth (AOD) over the oceans adjacent to East Asia increased by 3–8% yr<sup>−1</sup> to a peak around 2005–2006 and subsequently decreased by 2–7% yr<sup>−1</sup>, based on observations by the Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA's Terra satellite and simulations by a chemical transport model. This trend is consistent with ground-based observations of aerosol particles at a mountainous background observation site in central Japan. These fluctuations in SO<sub>2</sub> emission intensity and fine-mode AOD are thought to reflect the widespread installation of fuel-gas desulfurization (FGD) devices in power plants in China, because aerosol sulfate is a major determinant of the fine-mode AOD in East Asia. Using a chemical transport model, we confirmed that the contribution of particulate sulfate to the fine-mode AOD is more than 70% of the annual mean and that the abovementioned fluctuation in fine-mode AOD is caused mainly by changes in SO<sub>2</sub> emission rather than by other factors such as varying meteorological conditions in East Asia. A strong correlation was also found between satellite-retrieved SO<sub>2</sub> vertical column density and bottom-up SO<sub>2</sub> emissions, both of which were also consistent with observed fine-mode AOD trends. We propose a simplified approach for evaluating changes in SO<sub>2</sub> emissions in China, combining the use of modeled sensitivity coefficients that describe the variation of fine-mode AOD with changes in SO<sub>2</sub> emissions and satellite retrieval. Satellite measurements of fine-mode AOD above the Sea of Japan marked a 4.1% yr<sup>−1</sup> decline between 2007 and 2010, which corresponded to the 9% yr<sup>−1</sup> decline in SO<sub>2</sub> emissions from China during the same period

Pionic Atom Spectroscopy in the (d,3He) reaction at finite angles

We study the formation of deeply bound pionic atoms in the (d,3He) reactions theoretically and show the energy spectra of the emitted 3He at finite angles, which are expected to be observed experimentally. We find that the different combinations of the pion-bound and neutron-hole states dominate the spectra at different scattering angles because of the matching condition of the reaction. We conclude that the observation of the (d,3He) reaction at finite angles will provide the systematic information of the pionic bound states in each nucleus and will help to develop the study of the pion properties and the partial restoration of chiral symmetry in nuclei.Comment: 7 pages, 4 figures, 1 tabl

Precision spectroscopy of pionic 1s states of Sn nuclei and evidence for partial restoration of chiral symmetry in the nuclear medium

Deeply bound 1s states of $\pi^-$ in $^{115,119,123}$Sn were preferentially observed using the Sn($d$,$^3$He) pion-transfer reaction under the recoil-free condition. The 1s binding energies and widths were precisely determined, and were used to deduce the isovector parameter of the s-wave pion-nucleus potential to be $b_1 =-0.115\pm 0.007 ~m_{\pi}^{-1}$. The observed enhancement of $|b_1|$ over the free $\pi N$ value ($b_1^{\rm free}/b_1 = 0.78 \pm 0.05$) indicates a reduction of the chiral order parameter, $f^{*}_{\pi} (\rho)^2/f_{\pi}^2 \approx 0.64$, at the normal nuclear density, $\rho = \rho_0$.Comment: 4 pages including 3 postscript figures, RevTeX 4 with multirow.sty, submitted to Physical Review Letter

A search for deeply bound kaonic nuclear states

We have measured proton and neutron energy spectra by stopping negative kaons on liquid helium4. Two distinct peak structures were found on both spectra, which were assigned to the formation of new kinds of strange stribaryons. In this paper, we summarize both results.Comment: 7 pages, 3 figures, HYP2003 conference proceeding

Spectroscopy of eta'-nucleus bound states at GSI-SIS

The eta' meson mass may be reduced due to partial restoration of chiral symmetry. If this is the case, an eta'-nucleus system may form a nuclear bound state. We plan to carry out a missing-mass spectroscopy with the 12C(p,d) reaction at GSI-SIS. Peak structures corresponding to such a bound state may be observed even in an inclusive measurement, if the decay width is narrow enough.Comment: 4 pages, 2 figures, to appear in the proceedings of MESON2012 (12th International Workshop on Meson Production, Properties and Interaction), Krakow, Polan