Related papers: How can $X^{\pm}(5568)$ escape detection?
Very recently, the D0 collaboration has reported the observation of a narrow structure, $X(5568)$, in the decay process $X(5568)\to B^0_s\pi^\pm$ using the 10.4${\rm fb}^{-1}$ data of $p\bar p$ collision at $\sqrt s= 1.96$ TeV. This…
The recent observation by the D$\O$ collaboration of the first tetraquark candidate with four different quark flavors $(u, d, s$ and $ b)$ in the $B^0_s\pi^{\pm}$ channel having a narrow structure, has still not been confirmed by other…
Discovery of $X(5568)$ brings up a tremendous interest because it is very special, i.e. made of four different flavors. The D0 collaboration claimed that they observed this resonance through portal $X(5568)\to B_s\pi$, but unfortunately,…
We investigate the recent evidence for a charged $X(5568)$ meson as an exotic open-flavor tetraquark state $su\bar b\bar d$ with $J^P=0^+/1^+$ in the framework of QCD sum rules. We use the color antisymmetric $[\mathbf{\bar 3_c}]_{su}…
The $S$-wave eigenstates of tetraquarks of type $s u \bar d \bar b$ with J$^{P}$ = 0$^{+}$, 1$^{+}$ and 2$^{+}$ are studied within a simple quark model with chromomagnetic interaction and effective quark masses extracted from meson and…
Stimulated by the recent observation of the exotic $X(5568)$ state by D0 Collaboration, we study the four-quark system $us\bar{b}\bar{d}$ with quantum numbers $J^P=0^+$ in the framework of chiral quark model. Two structures,…
Inspired by the report of D0 Collaboration on the state $X(5568)$ with four different flavors, a similar state, $ud\bar{s}\bar{b}$ is investigated in the present work. The advantage of looking for this state over the state $X(5568)$ with…
We report evidence of a narrow structure, $X(5568)$, in the decay sequence $X(5568) \rightarrow B_s^0 \pi^{\pm}$, $B_s^0 \rightarrow J/\psi \phi$, $J/\psi\rightarrow \mu^+ \mu^-$, $\phi \rightarrow K^+K^-$. This is evidence for the first…
Stimulated by the recent observation of the $X(5568)$, we study the $X(5568)$ and its partners under the tetraquark scenario. In the framework of the color-magnetic interaction, we estimate the masses of the partner states of the $X(5568)$…
We use a combination of quark-antiquark and $B^{(*)}K$ interpolating fields to predict the mass of two QCD bound states below the $B^*K$ threshold in the quantum channels $J^P=0^+$ and $1^+$. The mesons correspond to the b-quark cousins of…
The exotic state $X(5568)$ which was observed by D0 Collaboration is very likely to be a tetraquark state with four different valence quark flavors, though the existence was not confirmed by other collaborations. The possibility of such…
The parameters, i.e. the mass and current coupling of the exotic $X(5568)$ state observed by the D0 Collaboration as well as the decay width of the process $X \to B_s^{0}\pi^{+}$ are explored using $B\bar{K}$ molecule assumption on its…
In a one-boson-exchange model, we study molecular states of double-charm baryon ($\Xi_{cc}(3621)$) and a charmed meson ($D$ and $D^*$). Our model indicates that there exist two possible triple-charm molecular pentaquarks, a $\Xi_{cc}D$…
A variety of options for interpreting the D\O{} state, $X(5568)$, are examined. We find that threshold, cusp, molecular, and tetraquark models are all unfavoured. Several experimental tests for unravelling the nature of the signal are…
We scrutinize recent QCD spectral sum rules (QSSR) results to lowest order (LO) predicting the masses of the BK molecule and (su)\bar(bd) four-quark states. We improve these results by adding NLO and N2LO corrections to the PT contributions…
The $D_s(2320)$ state recently observed by BaBar in the $D_s^+\pi^0$ channel may be the first of a host of $cq\bar q\bar q$ four-quark states. We give a phenomenological account of the masses and decay modes. The isosinglet $D_s(2320)$…
In the framework of the quark delocalization color screening model, we investigate tetraquarks composed of $us\bar{d}\bar{b}$ and $ud\bar{s}\bar{b}$ in two structures: meson-meson structure and diquark-antidiquark structure. Neither bound…
We analyze the possibility of the existence of a fully exotic pentaquark state $udsc\bar{b}$, which is made from the five different flavors participarting in the strong interactions. We investigate the coupled channel effects of the…
Beauty tetraquark states $X(\bar b q'q'' \bar q )$ composed of $ \bar b s u \bar d$, $\bar b d s \bar u$, and $\bar b u d \bar s$, are unique that all the four valence quarks are different. Although the claim of existence of the first two…
In this article, we take the $X(5568)$ as the diquark-antidiquark type tetraquark state with the spin-parity $J^P=0^+$, construct the scalar-diquark-scalar-antidiquark type current, carry out the operator product expansion up to the vacuum…