Direct CP violation in charm at Belle

Using the full data sample collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider, we have searched for CP violation of charmed mesons in $D^+\rightarrow K^0_S\pi^+$ and $D^0\rightarrow h^+h^-$ decays, where $h$ denotes $K$ and $\pi$. We observe evidence for CP violation in $D^+\rightarrow K^0_S\pi^+$ decay with 3.2 standard deviations away from zero, $(-0.363\pm0.094\pm0.067)$, while the asymmetry is consistent with the expected CP violation due to the neutral kaon in the final state. No evidence for CP violation in $D^0\rightarrow h^+h^-$ is observed with $A^{KK}_{CP}=(-0.32\pm0.21\pm0.09)$ and $A^{\pi\pi}_{CP}=(+0.55\pm0.36\pm0.09)$. The CP asymmetry difference between $D^0\rightarrow K^+K^-$ and $D^0\rightarrow\pi^+\pi^-$ decays is also measured with $\Delta A^{hh}_{CP}=(-0.87\pm0.41\pm0.06)$, which is 2.1 standard deviations away from zero and supports recent LHCb and CDF measurements.Comment: Proceedings of the 36th International Conference on High Energy Physics - ICHEP 2012; July 4-11 2012; Melbourne, Australi

First Axion Dark Matter Search with Toroidal Geometry

We report the first axion dark matter search with toroidal geometry. Exclusion limits of the axion-photon coupling $g_{a\gamma\gamma}$ over the axion mass range from 24.7 to 29.1 $\mu$eV at the 95\% confidence level are set through this pioneering search. Prospects for axion dark matter searches with larger scale toroidal geometry are also given.Comment: Contributed to the 13th Patras Workshop on Axions, WIMPs and WISPs, Thessaloniki, May 15 to 19, 201

Effect of nuclear interactions of neutral kaons on CP asymmetry measurements

We examine the effect of the difference in nuclear interactions of ${K}^0$ and $\bar{K}^0$ mesons on the measurement of CP asymmetry for experiments at $e^+e^-$ colliders - charm and $B$-meson factories. We find that this effect on CP asymmetry can be as large as 0.3%, and therefore sufficiently significant in interpreting measurements of CP asymmetry when neutral kaons are present in the final state.Comment: accepted to PR

Search for the Sagittarius tidal stream of axion dark matter around 4.55 μ\mueV

We report the first search for the Sagittarius tidal stream of axion dark matter around 4.55 $\mu$eV using CAPP-12TB haloscope data acquired in March of 2022. Our result excluded the Sagittarius tidal stream of Dine-Fischler-Srednicki-Zhitnitskii and Kim-Shifman-Vainshtein-Zakharov axion dark matter densities of $\rho_a\gtrsim0.184$ and $\gtrsim0.025$ GeV/cm$^3$, respectively, over a mass range from 4.51 to 4.59 $\mu$eV at a 90\% confidence level.Comment: 6 pages, 5 figures, 1 table, Proceedings of the European Physical Society Conference on High Energy Physics (EPS-HEP2023), Hamburg, Germany, August 202

First axion dark matter search with toroidal geometry

We firstly report an axion haloscope search with toroidal geometry. In this pioneering search, we exclude the axion-photon coupling $g_{a\gamma\gamma}$ down to about $5\times10^{-8}$ GeV$^{-1}$ over the axion mass range from 24.7 to 29.1 $\mu$eV at a 95\% confidence level. The prospects for axion dark matter searches with larger scale toroidal geometry are also considered.Comment: 5 pages, 5 figures, 1 table and to appear in PRD-R