Related papers: Tetraquark interpretation of $e^+ e^- \to \Upsilon…
Recently LHCb declared a new structure $X(6900)$ in the final state di-$J/\psi$ which is popularly regarded as a $cc$-$\bar c\bar c$ tetraquark state. %popularly. Within the Bethe-Salpeter (B-S) frame we study the possible $cc$-$\bar c\bar…
We study strong decays of the possible fully-charm tetraquarks recently observed by LHCb, and calculate their relative branching ratios through the Fierz rearrangement. Together with our previous QCD sum rule study [Phys. Lett. B 773, 247…
The internal structure of the light scalar meson $a_0(980)$ is explored in the three-body $D$ decays of $D\to a_0(980)P\to P_1P_2P$ through the intermediate state $a_0(980)$, where $P$ denotes a pseudoscalar meson. The quasi-two-body $D\to…
New BES and Belle data show a peak in the Y(4260) decay into J/psi plus one charged pion. We point out that the peak might correspond to a charged resonance at about 3880 MeV predicted time ago within a tetraquark model. The same tetraquark…
By analyzing the data sets of 17.3, 6.5 and 1.0 pb$^{-1}$ taken, respectively, at $\sqrt s= 3.773$, 3.650 and 3.6648 GeV with the BES-II detector at the BEPC collider, we measure the observed cross sections for $e^+e^-\to…
The production of $J/\psi$ mesons in continuum $e^+e^-$ annihilations has been studied with the BABAR detector at energies near the $\Upsilon(4S)$ resonance, approximately 10.6 GeV. The mesons are distinguished from $J/\psi$ production in B…
We report searches for the processes $e^+e^-\to\pi^+\pi^-\pi^0\chi_{bJ}$ and $e^+e^-\to\phi\chi_{bJ}$ (J=1,2) based on data samples collected by the Belle experiment at the KEKB collider. We report the first observation of the process…
Possibility of an axial vector isoscalar tetraquark $ud\bar{s}\bar{s}$ is discussed. If a $f_1$ meson in the mass region $1.4-1.5$ GeV consists of four quarks $ns\bar{n}\bar{s}$, the mass of the isoscalar…
We will present a review of the most interesting results on rare B decays from the B Factories, based on the data collected by the BaBar and Belle detectors at asymmetric $e^+ e^-$ colliders at the center of mass energy of the…
In the framework of the chiral quark model along with complex scaling range, we perform a dynamical study on the low-lying $S$-wave doubly-heavy tetraquark states ($QQ\bar{q}\bar{q}$, $Q=c, b$ and $q=u, d$) with an accurate computing…
We report improved measurements of branching fractions for $B\to K\pi$, $\pi^+\pi^-$, $\pi^+\pi^0$ and $K\bar{K}$ decays based on a data sample of 85.0 million $B\bar{B}$ pairs collected at the $\Upsilon (4S)$ resonance with the Belle…
The cross sections for e+e- to pi+pi-J/psi, pi+pi-psi(2S), K+K-J/psi, DDbar, DDbar pi, D*Dbar, and D*D*bar are measured using data sample collected on or near the Upsilon(4S) resonance with the Belle detector at KEKB. A peak near 4.25…
The top quark mass was measured in the channels $t\bar{t} \to \mathrm{lepton+jets}$ and $t\bar{t} \to \mathrm{dilepton}$ (lepton=$e, \mu$) based on ATLAS data recorded in 2011. The data were taken at the LHC with a proton--proton…
We report the first measurement of the absolute branching fraction e^+e^- --> B0B0bar at the Upsilon(4S) resonance using data collected with the BABAR detector at the PEP-II asymmetric-energy e^+e^- storage ring. The analysis is performed…
Parameters of the heavy four-quark scalar meson $T_{\mathrm{bc\overline{b} \overline{c}}}$ with content $bc \overline{b}\overline{c}$ are calculated by means of the sum rule method. This structure is considered as a diquark-antidiquark…
A complete classification of $qq \bar q \bar q$ tetraquark states in terms of the spin-flavour, colour and spatial degrees of freedom has been constructed. The permutational symmetry properties of both the spin-flavour and orbital parts of…
Decays of the fully beauty four-quark structures $X_{\mathrm{4b}}$ and $T_{ \mathrm{4b}}$ to $B$ meson pairs are investigated in the framework of QCD three-point sum rule method. We model the scalar exotic mesons $X_{\mathrm{4b }}$ and…
We report evidence for the decays $B^0\to D_s^{+} \pi^-$ and $B^0\to D_s^{-} K^+$ and the results of a search for $B^0 \to D_s^{*+} \pi^-$ and $B^0\to D_s^{*-} K^+$ in a sample of 84 milion Y(4S) decays into $B\bar{B}$ pairs collected with…
The BaBar experiment has discovered a narrow state, denoted as D*_{sJ}(2317)+, near 2.32 GeV/c^2 in the D+s pi^0 invariant mass distribution from inclusive $e^{+}e^{-}$ interactions at center-of-mass energies near 10.6 GeV. The same…
We report the results of the first search for the decay $B_s^0\rightarrow\pi^0\pi^0$ using $121.4\ \rm fb^{-1}$ of data collected at the $\Upsilon(5\rm S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider.…