Line Shapes of the Z(4430)

Abstract

The Belle Collaboration recently discovered the first manifestly exotic meson: Z^+(4430), which decays into psi' pi^+ and therefore has quark content c c-bar u d-bar. The proximity of its mass to the D_1 D-bar^* threshold has motivated the interpretation of the Z^+ as a charm meson molecule whose constituents are an S-wave superposition of D_1^+ D-bar^{*0}$and{D}^{\ast +}D-ba{r}_1^0$. If this interpretation is correct, the small ratio of the binding energy of the Z^+ to the width Gamma_1 of its constituent D_1 can be exploited to predict properties of its line shapes. Its full width at half maximum in the channel psi' pi^+ should be approximately sqrt{3} Gamma_1 = 35 MeV, which is consistent with the measured width of the Z^+. The Z^+ should also decay into D^* D-bar^* pi through decay of its constituent D_1. The peak in the line shape for D^* D-bar^* pi should be at a higher energy than the peak in the line shape for psi' pi^+ by about Gamma_1/sqrt{12} = 6 MeV. The line shape in D^* D-bar^* pi should also be broader and asymmetric, with a shoulder on the high energy side that can be attributed to a threshold enhancement in the production of D_1 D-bar^*.

4 pages, 1 figure

References in corpus (12)

• Observation of a resonance-like structure in the pi^+- psi' mass distribution in exclusive B-->K pi^+- psi' decays
• Reconciling the X(3872) with the near-threshold enhancement in the D^0\bar{D}^{*0} final state
• Line Shapes of the X(3872)
• Is Z^+(4430) a loosely bound molecular state?
• Indications of a Four-Quark Structure for the X(3872) and X(3876) Particles from Recent Belle and BABAR Data
• QCD sum rules study of the meson Z^+(4430)
• The Effects of Charged Charm Mesons on the Line Shapes of the X(3872)
• Threshold effect and π^\pm ψ(2S) peak
• A Uniform Description of the States Recently Observed at B-factories
• Isospin properties of the X state near the D {\bar D}^{*} threshold
• Partners of Z(4430) and Productions in B Decays
• Bottomed Analog of Z+(4433)

Cited by in corpus (8)

• Heavy quarkonium: progress, puzzles, and opportunities
• Observation of the resonant character of the $Z(4430{)}^{-}$ state
• Four-Quark Hadrons: an Updated Review
• Analysis of the $Z(4430)$ as the first radial excitation of the $Z_c(3900)$
• Treating $Z_c(3900)$ and $Z(4430)$ as the ground-state and first radially excited tetraquarks
• Resolving the puzzling decay patterns of charged $Z_c$ and $Z_b$ states
• Mass spectrum of the axial-vector hidden charmed and hidden bottom tetraquark states
• Possible tetraquark states in the ${\pi }^{+}{\chi }_{c1}$ invariant mass distribution