Abstract
The weak decays of the axial-vector tetraquark $T_{bb;\bar{u} \bar{d}}^{-}$ to the scalar state $Z_{bc;\bar{u} \bar{d}}^{0}$ are investigated using the QCD three-point sum rule approach. In order to explore the process $T_{bb; \bar{u} \bar{d}}^{-} \to Z_{bc;\bar{u} \bar{d}}^{0}l \bar{\nu_l}$, we recalculate the spectroscopic parameters of the tetraquark $T_{bb;\bar{u} \bar{d}}^{-}$ and find the mass and coupling of the scalar four-quark system $Z_{bc;\bar{u} \bar{d}}^{0}$, which are important ingredients of calculations. The spectroscopic parameters of these tetraquarks are computed in the framework of the QCD two-point sum rule method by taking into account various condensates up to dimension ten. The mass of the $T_{bb;\bar{u} \bar{ d}}^{-}$ state is found to be $m=(10035~\pm 260)~\mathrm{MeV}$, which demonstrates that it is stable against the strong and electromagnetic decays. The full width $\Gamma$ and mean lifetime $\tau$ of $T_{bb;\bar{u} \bar{d} }^{-}$ are evaluated using its semileptonic decay channels $T_{bb; \bar{u} \bar{d}}^{-} \to Z_{bc;\bar{u} \bar{d}}^{0}l \bar{\nu_l}$, $l=e,\mu$ and $\tau$. The obtained results, $\Gamma=(7.17\pm 1.23)\times 10^{-8\ \ } \mathrm{MeV}$ and $\tau =9.18_{-1.34}^{+1.90}~\mathrm{fs}$, can be useful for experimental investigations of the doubly-heavy tetraquarks.
Highlights
Assumptions about the existence of four-quark bound states were made in an early stage of QCD and aimed to explain some of the unusual features of meson spectroscopy
This conclusion is valid even when taking into account uncertainties inherent to the sum rule computations
Our result for m is smaller than the predictions made in Refs. [18] and [26] using the QCD sum rule method and phenomenological model estimations, respectively
Summary
Z0bc;ud ̄ lνl, we recalculate the spectroscopic parameters of the tetraquark T−bb;ud ̄ and find the mass and coupling of the scalar four-quark system Z0bc;ud ̄ , which are important ingredients of calculations. Ð10035 Æ 260Þ MeV, which demonstrates that it is stable against the strong and electromagnetic decays
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have