Related papers: Z+(4430) as a cusp in D*(2010)Dbar_1(2420)
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…
We discuss exotic states X(3872) and $Z^+(4430)$, observed recently in experiment Belle. The QCD-string based explanation is suggested.
We present the interpretation that the recently discovered Z^+(4430) by the Belle Collaboration can be a radial excitation of the cs-bar state. We give an explicit cs-bar candidate for this state by calculating the mass value in our…
We study the possibility that the $Z^+(4430)$ state observed by Belle is a $D_1D^*$ (or $D_1'D^*$) resonance in S-wave. Focusing on its decays, We find that the open-charm decay into $D^*D^*\pi$ is dominant. Furthermore, we use the…
$Z_c(4430)$ discovered by the Belle and confirmed by the LHCb in $\bar{B}^0\to\psi(2S)K^-\pi^+$ is generally considered to be a charged charmonium-like state that includes minimally two quarks and two antiquarks. $Z_c(4200)$ found in…
In a previous paper we suggested an explanation for the peak designated as $Z(4430)^+$ in the $\psi^\prime\pi^+$ mass spectrum, observed by Belle in ${\bar{\!B}} \to {\psi^\prime} \pi^+ K$ decays, as an effect of $\bar{\!D}{}^{\,*0}D^{\,+}…
We investigated the bound state problem of the S wave charged $D_1 \bar{D}^*$ ($D_1' \bar{D}^*$) system in a chiral quark model by solving the resonating group method equation. Our preliminary study does not favor the molecular assumption…
The observation of $Z_c(3900)$ by the BESIII collaboration in the invariant mass spectrum of $J/\psi\pi^\pm$ in $e^+e^-\to J/\psi\pi^+\pi^-$ at the center of mass 4.260 GeV suggests the existence of a charged $\bar D D^*+D\bar D^*$…
We perform a full amplitude analysis of B0 -> psi' K+ pi- decays, with psi' -> mu+ mu- or e+ e-, to constrain the spin and parity of the Z(4430)-. The J^P=1+ hypothesis is favored over the 0-, 1-, 2- and 2+ hypotheses at the levels of 3.4…
The threshold pbar-p peak in BES data for J/\Psi to gamma-pbar-p may be fitted as a cusp. It arises from the well known threshold peak in pbar-p elastic scattering due to annihilation. Several similar examples are discussed. The PS185 data…
We use QCD sum rules to study the recently observed meson $Z^+(4430)$, considered as a $D^*D_1$ molecule with $J^{P}=0^{-}$. We consider the contributions of condensates up to dimension eight and work at leading order in $\alpha_s$. We get…
Several $X$ and $Z_{cs}$ exotic hadrons were claimed in the LHCb's amplitude analysis on $B^+\to J/\psi \phi K^+$. The data shows that all the peaks and also dips in the spectra are located at thresholds of seemingly relevant meson-meson…
Invoked by the recent observation of $Y(4390)$ at BESIII, which is about 40 MeV below the $D^*(2010)\bar{D}_1(2420)$ threshold, we investigate possible bound and resonance states from the $D^*(2010)\bar{D}_1(2420)$ interaction with the…
Since $Z^+(4430)$ lies very close to the threshold of $D^\ast{\bar D}_1$, we investigate whether $Z^+(4430)$ could be a loosely bound S-wave state of $D^\ast{\bar D}_1$ or $D^\ast{\bar D}^\prime_1$ with $J^P=0^-, 1^-, 2^-$, i.e., a…
A resonance-like structure as narrow as 10 MeV is observed in the $K^-p$ invariant mass distributions in $\Lambda_c^+\to p K^- \pi^+$ at Belle. Based on the large data sample of about 1.5 million events and the small bin width of just 1 MeV…
We observe a narrow peaking structure in the $pK^{-}$ invariant-mass spectrum near the $\Lambda\eta$ threshold. The peak is clearly seen in 1.5 million events of $\Lambda_{c}^{+} \rightarrow p K^{-} \pi^{+}$ decay using the $980~{\rm…
The X(3872) and Z(4430) are candidates of tetraquark state with a ccbar pair. We present results from Belle recently updated for the mass, branching fractions etc. in different production/decay processes of the X(3872). Results from a…
We reexamine whether $Z^+(4430)$ could be a $D_1'-{D}^*$ or $D_1-{D}^*$ molecular state after considering both the pion and $\sigma$ meson exchange potentials and introducing the form factor to take into account the structure effect of the…
The proximity of ${\rm Z}^+(4430)$ to the ${\rm D^{*}\bar{D}_1}$ threshold suggests that it may be a ${\rm D^{*}\bar{D}_1}$ molecular state. The ${\rm D^{*}\bar{D}_1}$ system has been studied dynamically from quark model, and state mixing…
Belle report data on Upsilon (5S) -> Upsilon(1S,2S,3S)-piplus-piminus and chi_b(1P,2P)-piplus-piminus; they observe peaks in Upsilon-pi and chi_b-pi consistent with J^P=1^+. They interpret the peaks as molecular states Z_b(10608) and…