Resonant structures in B^0→ψ^'π^-K^+ decays are analyzed by performing a four-dimensional fit of the decay amplitude, using pp collision data corresponding to 3 fb^-1 collected with the LHCb detector. The data cannot be described with K^+π^- resonances alone, which is confirmed with a model-independent approach. A highly significant Z(4430)^-→ψ^'π^- component is required, thus confirming the existence of this state. The observed evolution of the Z(4430)^- amplitude with the ψ^'π^- mass establishes the resonant nature of this particle. The mass and width measurements are substantially improved. The spin parity is determined unambiguously to be 1^+.
Observation of the resonant character of the Z(4430)(-) state
VELTRI, MICHELE;
2014
Abstract
Resonant structures in B^0→ψ^'π^-K^+ decays are analyzed by performing a four-dimensional fit of the decay amplitude, using pp collision data corresponding to 3 fb^-1 collected with the LHCb detector. The data cannot be described with K^+π^- resonances alone, which is confirmed with a model-independent approach. A highly significant Z(4430)^-→ψ^'π^- component is required, thus confirming the existence of this state. The observed evolution of the Z(4430)^- amplitude with the ψ^'π^- mass establishes the resonant nature of this particle. The mass and width measurements are substantially improved. The spin parity is determined unambiguously to be 1^+.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
