H. Nakazawa

Measurement of γγ → pp̄ production at Belle

A high precision study of the process gamma gamma -> p p-bar has been performed using a data sample of 89/fb collected with the Belle detector at the KEKB e+e- collider. The cross section of p p-bar production has been measured at two-photon center-of-mass (c.m.) energies between 2.025 and 4.0 GeV and in the c.m. angular range of |cos(theta^*)| eta_c -> p p-bar is observed and the product of the two-photon width of the eta_c and its branching ratio to p p-bar is determined.

Study of decay mechanisms in B-->Lambda(+)(c)p pi(-) decays and observation of low-mass structure in the Lambda(+)(c)p system

Using a sample of 152 million BBbar pairs accumulated with the Belle detector at the KEKB e+e- collider, we perform a Dalitz plot analysis of the three-body charmed decay B- ->Lambda_c+ p_bar pi-. The intermediate two-body decay B- ->Sigma_c(2455)0 p_bar is observed for the first time with a branching fraction of (3.67^{+0.74}_{-0.66}+-0.36+-0.95)x10^(-5) and a statistical significance of 8.4sigma. We also observe a low-mass enhancement in the (Lambda_c+ p_bar) system, which can be parameterized as a Breit-Wigner function with a mass of (3.35^{+0.01}_{-0.02}+-0.02)GeV/c^2 and a width of (0.07^{+0.04}_{-0.03}+-0.04)GeV/c^2. We measure the product of the corresponding decay branching fractions to be (3.87^{+0.77}_{-0.72}+-0.43+-1.01)x10^(-5)

Search for CP violation in tau -> K^0_S pi nu_tau decays at Belle

with a statistical significance of 6.2sigma. The errors are statistical, systematic, and that of the Lambda_c^+ ->pK-pi+ decay branching fraction.

Observation of the decays B0 → K+π -π0 and B0 → ρ-K +

We report on a search for CP violation in tau(+/-) -> K-S(0)pi(+/-)nu(tau) decays using a data sample of 699 fb(-1) collected by the Belle experiment at the KEKB electron-positron asymmetric-energy collider. The CP asymmetry is measured in four bins of the invariant mass of the K-S(0)pi(+/-) system and found to be compatible with zero with a precision of O(10(-3)) in each mass bin. Limits for the CP violation parameter Im(eta(S)) are given at the 90% confidence level. These limits are |Im(eta(S))| < 0.026 or better, depending on the parametrization used to describe the hadronic form factors, and improve upon previous limits by 1 order of magnitude.

Search for B- → J/ ψΛp̄ decay 017101

We report the observation of B0 decays to the K+π-π0 final state using a data sample of 78 fb-1 collected by the Belle detector at the KEKB e+e- collider. With no assumptions about intermediate states in the decay, the branching fraction is measured to be (36.6-4.3+4.2±3.0)×10-6. We also search for B decays to intermediate two-body states with the same K+π-π0 final state. Significant B signals are observed in the ρ(770)-K+ and K*(892)+π- channels, with branching fractions of (15.1-3.3-1.5-2.1+3.4+1.4+2.0)×10-6 and (14.8-4.4-1.0-0.9+4.6+1.5+2.4) ×10-6, respectively. The first error is statistical, the second is systematic and the third is due to the largest possible interference. Contributions from other possible two-body states will be discussed. No CP asymmetry is found in the inclusive K+π-π0 or ρ-K+ modes, and we set 90% confidence level bounds on the asymmetry of -0.12

Two-photon processes at Belle

We report the results of a search for

Study of time-dependent CP violation in B0 → J/ Ψπ0 decays 261801

B^{-} \to \jpsi \Lambda \pbar

Measurement of the CP asymmetry in B → Xsγ

based on a data set of 78 fb

Physics achievements from the Belle experiment

^{-1}

Study of CP violating effects in time dependent B0(B̄ 0) → D(*)∓ π± decays

data collected at the