Z(4430)

Z(4430) is a mesonic resonance discovered by the Belle experiment.^[1][2]. It has a mass of 4,430 MeV/c². This resonance has not yet been seen in other experiments.

Unlike the X(3872) meson discovered by the same experiment, this particle has a charge and is a tetraquark meson candidate. However, its quantum numbers seem to be those of a pion, which is inconsistent with the tetraquark interpretation.

References

1. ^ Choi, S.-K.; et al. (Belle Collaboration) (2007). "Observation of a resonance-like structure in the π±
   Ψ′ mass distribution in exclusive B→Kπ±
   Ψ′ decays". Physical Review Letters 100 (14). arXiv:0708.1790. Bibcode 2008PhRvL.100n2001C. doi:10.1103/PhysRevLett.100.142001. 
2. ^ "Belle Discovers a New Type of Meson" (Press release). KEK. 2007. http://www.kek.jp/intra-e/press/2007/BellePress11e.html. Retrieved 2009-06-20.