How can $X^{\pm }(5568)$ escape detection?

Abstract

Multi-quark states were predicted by Gell-Mann when the quark model was first formulated. Recently, numerous exotic states that are considered to be multi-quark states have been experimentally confirmed (four-quark mesons and five-quark baryons). Theoretical research indicates that the four-quark state might comprise molecular and/or tetraquark structures. We consider that the meson containing four different flavors $su\bar{b}\bar{d}$ should exist and decay via the $X(5568)\to B_s\pi$ channel. However, except for the D0 collaboration, all other experimental collaborations have reported negative observations for $X(5568)$ in this golden portal. This contradiction has stimulated the interest of both theorists and experimentalists. To address this discrepancy, we propose that the assumed $X(5568)$ is a mixture of a molecular state and tetraquark, which contributes destructively to $X(5568)\to B_s\pi$. The cancellation may be accidental and it should be incomplete. In this scenario, there should be two physical states with the same flavor ingredients, with spectra of $5344\pm 307$ and $6318\pm 315$. $X(5568)$ lies in the error range of the first state. We predict the width of the second state (designated as $S_2$) as $\Gamma (X_{S_2}\to B_s\pi )=224\pm 97$ MeV. We strongly suggest searching for it in future experiments.

pages 4. Accepted by phys. lett. B

References in corpus (11)

• Observation of a resonance-like structure in the pi^+- psi' mass distribution in exclusive B-->K pi^+- psi' decays
• Exotic meson-meson molecules and compact four--quark states
• Search for structure in the $B_s^0{\pi }^{\pm }$ invariant mass spectrum
• Search for the X(5568) state decaying into ${\mathrm{B}}_{\mathrm{s}}^0{\pi }^{\pm }$ in proton-proton collisions at $\sqrt{s}=$ 8 TeV
• Search for a Structure in the $B_s^0{\pi }^{\pm }$ Invariant Mass Spectrum with the ATLAS Experiment
• A search for the exotic meson $X(5568)$ with the Collider Detector at Fermilab
• $B_s{\pi }^{+}$ scattering and search for X(5568) with lattice QCD
• Study of the $X^{\pm }(5568)$ state with semileptonic decays of the $B_s^0$ meson
• Is the newly reported $X(5568)$ a $B\bar{K}$ molecular state?
• Where does the X(5568) structure come from?
• $B_s\pi$--$B\bar{K}$ interactions in finite volume and the $X(5568)$

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• Mass Spectrum of Exotic X(5568) State via Artificial Neural Network
• Studying the bound state of the $B\bar{K}$ system in the Bethe-Salpeter formalism
• Chiral excitations of open-beauty systems