The cross section for ee+ e- → π+ π- J/ψ between 3.8 and 5.5 GeV is measured with a 967  fb(-1) data sample collected by the Belle detector at or near the Υ(nS) (n = 1,2,…,5) resonances. The Y(4260) state is observed, and its resonance parameters are determined. In addition, an excess of π+ π- J/ψ 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) → π+ π- J/ψ decays, a structure is observed in the M(π(±)J/ψ) mass spectrum with 5.2σ significance, with mass M = (3894.5 ± 6.6 ± 4.5)  MeV/c2 and width Γ = (63 ± 24 ± 26)  MeV/c2, where the errors are statistical and systematic, respectively. This structure can be interpreted as a new charged charmoniumlike state.

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We study B --> K(*)l+l- decays (l = e, mu) based on a data sample of 657 x 10(6) BB 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(FB)) as functions of q2 = M(ll)(2)c2. The fitted A(FB) spectrum exceeds the standard model expectation by 2.7 standard deviations. The measured branching fractions are B(B --> K*l+l-) = (10.7(-1.0)(+1.1) +/- 0.9) x 10(-7) and B(B --> Kl+l-) = (4.8(-0.4)(+0.5) +/- 0.3) x 10(-7), where the first errors are statistical and the second are systematic, with the muon to electron ratios R(K*) = 0.83 +/- 0.17 +/- 0.08 and R(K) = 1.03 +/- 0.19 +/- 0.06.

We report the results of a study of the exclusive semileptonic decays B − → π 0 ℓ −ν ℓ ,B 0 → π + ℓ −ν ℓ , B − → ρ 0 ℓ −ν ℓ ,B 0 → ρ + ℓ −ν ℓ and B − → ωℓ −ν ℓ , where ℓ represents an electron or a muon. The events are tagged by fully reconstructing a second B meson in the event in a hadronic decay mode. The measured branching fractions are B(B − → π 0 ℓ −ν ℓ) = (0.80 ± 0.08 ± 0.04) × 10 −4 , B(B 0 → π + ℓ −ν ℓ) = (1.49 ± 0.09 ± 0.07) × 10 −4 , B(B − → ρ 0 ℓ −ν ℓ) = (1.83 ± 0.10 ± 0.10) × 10 −4 , B(B 0 → ρ + ℓ −ν ℓ) = (3.22 ± 0.27 ± 0.24) × 10 −4 , and B(B − → ωℓ −ν ℓ) = (1.07 ± 0.16 ± 0.07) × 10 −4 , where the first error is statistical and the second one is systematic. The obtained branching fractions are inclusive of soft photon emission. We also determine the branching fractions as a function of the 4-momentum transfer squared to the leptonic system q 2 = (p ℓ + p ν) 2 , where p ℓ and p ν are the lepton and neutrino 4-momenta, respectively. Using the pion modes, a recent LCSR calculation, lattice QCD results and a model-independent description of the hadronic form factor, a value of the CKM matrix element |V ub | = (3.52 ± 0.29) × 10 −3 is extracted. For the first time, a charmless state with invariant mass greater than 1 GeV/c 2 , which might be dominated by the decay B − → f 2 ℓ −ν ℓ , is observed. These results are obtained from a 711 fb −1 data sample that contains 772 × 10 6 BB pairs, collected near the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e + e − collider.

The cross section for e(+)e(-)-->pi(+)pi(-)J/psi between 3.8 and 5.5 GeV/c(2) is measured using a 548 fb(-1) data sample collected on or near the Upsilon(4S) resonance with the Belle detector at KEKB. A peak near 4.25 GeV/c(2), corresponding to the so called Y(4260), is observed. In addition, there is another cluster of events at around 4.05 GeV/c(2). A fit using two interfering Breit-Wigner shapes describes the data better than one that uses only the Y(4260), especially for the lower-mass side of the 4.25 GeV enhancement.