Probing an axial-vector tetraquark $Z_s$ via its semileptonic decay $Z_s \to X(4274)\overline{l} \nu_l$

Abstract

The semileptonic decays of the open charm-bottom axial-vector tetraquark $ Z_{s}=[cs][\overline{b}\overline{s}]$ to $X(4274)\overline{l} \nu_l$, $l=e, \mu, \tau $ are explored by means of the QCD three-point sum rule method. Both $Z_{s}$ and $X(4274)=[cs][\overline{c}\overline{s}]$ are treated as color sextet diquark-antidiquark states. The full width of the decays $Z_s \to X(4274)\overline{l} \nu_l$ is found. Obtained predictions for $ \Gamma(Z_s \to X(4274)\overline{l} \nu_l)$ demonstrate that, as in the case of the conventional hadrons, the semileptonic transitions form a very small part of its full width.