A Search for X^0(214) at Belle

초록

The HyperCP experiment at Fermilab reported an observation of three Σ+ to p μ+μ- decays. The reconstructed mass of the muon pairs in the observed events was measured to be about 214 MeV with mass resolution within the detector resolution of 1 MeV. Thus, decays might interpreted as a two-body decay, Σ+ to p X0, X0 to μ+μ-. Several theoretical papers were followed to interpret for X0(214); a pseudo-scalar (sgoldstino) particle with parity-conserving interaction in GMSB model and a light Higgs boson in NMSSM model. A large sample of B meson data at Belle would be of benefit to a search on X0(214) in b-quark sector. We used background Monte Carlo samples (1750 fb-1), and 605 fb-1 data sample collected by the Belle detector in KEKB　asymmetric energy e+e- collider. We present our progress on a search for the X0(214) from B0 decays with the assumption of the pseudo-scalar particle.