Vector resonance X1(2900) and its structure

The new vector resonance $X_1(2900)$ observed recently by LHCb in the $ D^{-}K^{+}$ invariant mass distribution decay $B^{+} \to D^{+}D^{-}K^{+}$ is studied to uncover internal structure of this state, and calculate its physical parameters. In present paper, X_1(2900)$ modeled as an exotic J^P=1^- $, built light diquark $u^{T}C\gamma_5d$ heavy antidiquark $\overline{c} \gamma_{\mu}\gamma_5C\overline{s}^{T}$. current coupling are computed using QCD two-point sum rule approach taking into account various vacuum condensates up dimension $10$. width saturated two channels $X_1 \overline{D}^{0}K^{0}$. strong couplings $g_1$ $g_2$ corresponding vertices $X_1D^{-}K^{+}$ $X_1\overline{D} ^{0}K^{0}$ evaluated context light-cone method technical tools soft-meson approximation. Results for $m=(2890~\pm 122)~\mathrm{MeV}$, full $\Gamma _{\mathrm{full}}=(93\pm 13)~\mathrm{MeV}$ smaller than their experimental values reported collaboration. Nevertheless, theoretical errors investigations, interpretation state tetraquark does not contradict data. We also point out that analysis $D^{+}K^{+}$ same B^{+} may reveal doubly charged four-quark structures [uc][\overline{s}\overline{d}]$.