Double-charm tetraquark under the complex scaling method

The LHCb Collaboration discovered a double-charm tetraquark ${T}_{cc}^{+}$ with very small width. We investigate the as $D{D}^{*}$ molecule ${J}^{P}={1}^{+}$ in framework of one-boson-exchange potential model. isospin breaking effect and $S\ensuremath{-}D$ wave coupling are taken into account carefully. adopt complex scaling method to study system obtain quasibound state corresponding ${T}_{cc}^{+}$. Its binding energy relative ${D}^{0}{D}^{*+}$ width $\ensuremath{-}354\text{ }\text{ }\mathrm{keV}$ 61 keV respectively. is found be enormous, $S$-wave ${D}^{+}{D}^{*0}$ components give dominant contributions probabilities 72.1% 27.1% In addition, we do not find any resonances system. As by-product, $X(3872)$ $(D{\overline{D}}^{*}\ensuremath{-}{D}^{*}\overline{D})/\sqrt{2}$ ${J}^{PC}={1}^{++}$. also $X(3872)$. ${D}^{0}{\overline{D}}^{*0}$ threshold $\ensuremath{-}111\text{ 26 keV, $({D}^{0}{\overline{D}}^{*0}\ensuremath{-}{D}^{*0}{\overline{D}}^{0})/\sqrt{2}$ component dominates this probability 92.7%.