The cross section for $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}J/\psi$ between 3.8 and 5.5 GeV is measured with a $967{\mathrm{fb}}^{-1}$ data sample collected by the Belle detector at or near the ${\rm Y}(nS)$ ($n=1,2,\dots ,5$) resonances. The $Y(4260)$ state is observed, and its resonance parameters are determined. In addition, an excess of ${\pi }^{+}{\pi }^{-}J/\psi$ production around 4 GeV is observed. This feature can be described by a Breit-Wigner parametrization with properties that are consistent with the $Y(4008)$ state that was previously reported by Belle. In a study of $Y(4260)\to {\pi }^{+}{\pi }^{-}J/\psi$ decays, a structure is observed in the $M({\pi }^{\pm }J/\psi )$ mass spectrum with $5.2\sigma$ significance, with mass $M=(3894.5\pm 6.6\pm 4.5)\mathrm{MeV}/c^2$ and width $\Gamma =(63\pm 24\pm 26)\mathrm{MeV}/c^2$, where the errors are statistical and systematic, respectively. This structure can be interpreted as a new charged charmoniumlike state.

A distinct peak is observed in the ${\pi }^{\pm }{\psi }^{\prime }$ invariant mass distribution near 4.43 GeV in $B\to K{\pi }^{\pm }{\psi }^{\prime }$ decays. A fit using a Breit-Wigner resonance shape yields a peak mass and width of $M=4433\pm 4(\mathrm{stat})\pm 2(\mathrm{syst})\mathrm{MeV}$ and $\Gamma ={45}_{-13}^{+18}(\mathrm{stat}{)}_{-13}^{+30}(\mathrm{syst})\mathrm{MeV}$. The product branching fraction is determined to be $\mathcal{B}\mathbf{(}{B}^0\to K^{\mp }{Z}^{\pm }(4430)\mathbf{)}\times \mathcal{B}\mathbf{(}{Z}^{\pm }(4430)\to {\pi }^{\pm }{\psi }^{\prime }\mathbf{)}=(4.1\pm 1.0(\mathrm{stat})\pm 1.4(\mathrm{syst}))\times {10}^{-5}$, where $Z^{\pm }(4430)$ is used to denote the observed structure. The statistical significance of the observed peak is $6.5\sigma$. These results are obtained from a $605{\mathrm{fb}}^{-1}$ data sample that contains $657\times {10}^6$ $B\overline{B}$ pairs collected near the ${\rm Y}(4S)$ resonance with the Belle detector at the KEKB asymmetric energy $e^{+}{e}^{-}$ collider.

We study $B\to K^{(*)}{\ell }^{+}{\ell }^{-}$ decays ($\ell =e$, $\mu$) based on a data sample of $657\times {10}^6$ $B\overline{B}$ pairs collected with the Belle detector at the KEKB $e^{+}{e}^{-}$ collider. We report the differential branching fraction, isospin asymmetry, $K^{*}$ polarization, and the forward-backward asymmetry ($A_{\mathrm{FB}}$) as functions of $q^2=M_{\ell \ell }^2{c}^2$. The fitted $A_{\mathrm{FB}}$ spectrum exceeds the standard model expectation by 2.7 standard deviations. The measured branching fractions are $\mathcal{B}(B\to K^{*}{\ell }^{+}{\ell }^{-})=({10.7}_{-1.0}^{+1.1}\pm 0.9)\times {10}^{-7}$ and $\mathcal{B}(B\to K{\ell }^{+}{\ell }^{-})=({4.8}_{-0.4}^{+0.5}\pm 0.3)\times {10}^{-7}$, where the first errors are statistical and the second are systematic, with the muon to electron ratios $R_{K^{*}}=0.83\pm 0.17\pm 0.08$ and $R_K=1.03\pm 0.19\pm 0.06$.