We report a measurement of the differential cross section of π 0 pair production in single-tag two-photon collisions, γ * γ → π 0 π 0 , in e + e − scattering. The cross section is measured for Q 2 3 up to 30 GeV 2 , where Q 2 is the negative of the invariant mass squared of the tagged photon, in the kinematic range 0.5 GeV < W < 2.1 GeV and | cos θ * | < 1.0 for the total energy and pion scattering angle, respectively, in the γ * γ center-of-mass system. The results are based on a data sample of 759 fb −1 collected with the Belle detector at the KEKB asymmetric-energy e + e − collider. The transition form factor of the f0(980) and that of the f2(1270) with the helicity-0, -1, and -2 components separately are measured for the first time and are compared with theoretical calculations.

We report inclusive and exclusive measurements for χc1 and χc2 production in B decays. We measure B(B → χc1X)= (3.03 ± 0.05(stat) ± 0.24(syst)) × 10 −3 and B(B → χc2X)= (0.70 ± 0.06(stat) ± 0.10(syst)) × 10 −3 . For the first time, χc2 production in exclusive B decays in the modes B 0 → χc2π − K + and B + → χc2π + π − K + has been observed, along with first evidence for the B + → χc2π + K 0 S decay mode. For χc1 production, we report the first observation in theUsing these decay modes, we observe a difference in the production mechanism of χc2 in comparison to χc1 in B decays. In addition, we report searches for X(3872) and χc1(2P ) in the B + → (χc1π + π − )K + decay mode. The reported results use 772 × 10 6 BB events collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e + e − collider.

We present a measurement of the branching fraction and the longitudinal polarization fraction of B 0 → ρ + ρ − decays, as well as the time-dependent CP violating parameters in decays into longitudinally polarized ρ + ρ − pairs with Belle's final data set of 772 × 10 6 BB pairs, at the Υ(4S) resonance, collected at the asymmetric-energy e + e − collider KEKB. We obtainA CP = 0.00 ± 0.10 (stat) ± 0.06 (syst),We perform an isospin analysis to constrain the CKM angle φ 2 and obtain two solutions with φ 2 = (93.7 ± 10.6) • , being most compatible with other Standard-Model based fits to the data.

We report the first measurement of the lepton forward-backward asymmetry AFB as a function of the squared four-momentum of the dilepton system, q 2 , for the electroweak penguin process B → Xsℓ + ℓ − with a sum of exclusive final states, where ℓ is an electron or a muon and Xs is a hadronic recoil system with an s quark. The results are based on a data sample containing 772 × 10 6 BB pairs recorded at the Υ(4S) resonance with the Belle detector at the KEKB e + e − collider. AFB for the inclusive B → Xsℓ + ℓ − is extrapolated from the sum of 10 exclusive Xs states whose invariant mass is less than 2 GeV/c 2 . For q 2 > 10.2 GeV 2 /c 2 , AFB < 0 is excluded at the 2.3σ level, where σ is the standard deviation. For q 2 < 4.3 GeV 2 /c 2 , the result is within 1.8σ of the Standard Model theoretical expectation.

No abstract