Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Gelb, M.*; 谷田 聖; Belle Collaboration*; 他185名*
Physical Review D, 98(11), p.112016_1 - 112016_13, 2018/12
被引用回数:15 パーセンタイル:61.5(Astronomy & Astrophysics)We present the result of the search for the rare meson decay of with . For the search the full data set recorded by the Belle experiment of integrated luminosity near the resonance is used. Signal candidates are reconstructed for photon energies larger than using a novel multivariate tagging algorithm. The novel algorithm fully reconstructs the second meson produced in the collision using hadronic modes and was specifically trained to recognize the signal signature in combination with hadronic tag-side meson decays. This approach greatly enhances the performance. Background processes that can mimic this signature, mainly charmless semileptonic decays and continuum processes, are suppressed using multivariate methods. The number of signal candidates is determined by analyzing the missing mass squared distribution as inferred from the signal side particles and the kinematic properties of the tag-side meson. No significant excess over the background-only hypothesis is observed and upper limits on the partial branching fraction with individually for electron and muon final states as well as for the average branching fraction of both lepton final states are reported. We find a Bayesian upper limit of at 90% CL and also report an upper limit on the first inverse moment of the light-cone distribution amplitude of the meson of at 90% CL.
増田 正孝*; 谷田 聖; Belle Collaboration*; 他185名*
Physical Review D, 97(5), p.052003_1 - 052003_20, 2018/03
被引用回数:6 パーセンタイル:33.27(Astronomy & Astrophysics)We report a measurement of the cross section for pair production in single-tag two-photon collisions, , for up to 30 GeV, where is the negative of the invariant mass squared of the tagged photon. The measurement covers the kinematic range 1.0 GeV 2.6 GeV and for the total energy and kaon scattering angle, respectively, in the center-of-mass system. These results are based on a data sample of 759 fb collected with the Belle detector at the KEKB asymmetric-energy collider. For the first time, the transition form factor of the meson is measured separately for the helicity-0, -1, and -2 components and also compared with theoretical calculations. Finally, the partial decay widths of the and mesons are measured as a function of .