The Belle collaboration observed a difference between direct charge-parity asymmetries for charged and neutral B meson decays into a kaon and a pion. This difference could be an indication of a new source of CP violation that is needed to explain the matter-dominated Universe.
COBISS.SI-ID: 21553703
We have studied hadronic tau decay modes involving an eta meson using 490 fb^{-1} of data collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. The obtained results are substantially more precise than previous measurements. The new measurements are compared with theoretical calculations based on the CVC hypothesis or the chiral perturbation theory. We also set upper limits on branching fractions for tau decays into K- Ks eta nu, pi- Ks pi0 eta nu, K- eta eta nu, pi- eta eta nu and non-resonant K- pi0 eta nu final states.
COBISS.SI-ID: 22564903
We studied B-->K(*) l+ l- decays (l=e,mu) based on a data sample of 657 million BB pairs collected with the Belle detector at the KEKB e+e- collider. We reported the differential branching fraction, isospin asymmetry, K* polarization, and the forward-backward asymmetry (AFB) as functions of q^2. The fitted AFB spectrum exceeds the Standard Model expectation by 2.7 standard deviations allowing for new physics.
COBISS.SI-ID: 23094055
We report on a search for the lepton flavor violating tau- -> mu- gamma and tau- -> e- gamma decays based on 535/fb of data accumulated at the Belle experiment. No signal is found and we set 90% confidence level upper limits on the branching ratios Br(tau- -> mu- gamma) < 4.5x10^-8 and Br(tau- -> e- gamma) < 1.2x10^-8.
COBISS.SI-ID: 22108711
The Belle II experiment is expected to produce 50 times more data than the existing Belle experiment. Such huge data production requires not only scalability with respect to the storage service but also scalability regarding the metadata service. There has already been a metadata service at the Belle experiment, but it is not proper for the Belle II experiment because it has scalability problems and it is not intended to be used in a distributed grid environment. To deal with these issues, we designed an advanced metadata service system based on AMGA.
COBISS.SI-ID: 24367655