Masses and magnetic moments of doubly heavy tetraquarks via diffusion Monte Carlo method

We present mass spectrum and magnetic moments of the $\overline{n}\overline{n}QQ$ states, where $n=u,d,s$ and $Q=c,b.$ We solve four-body Schrödinger equation with a quark potential model by using diffusion Monte Carlo (DMC) method. The quark potential is based on the Coulomb, confinement and spin–spin interaction terms. We find mass and magnetic moment of the ${T}_{\mathrm{cc}}^{+}$ state as ${M}_{{T}_{\mathrm{cc}}^{+}}=3892\phantom{\rule{3.33333pt}{0ex}}\text{MeV}$ and $\mu =0.28{\mu }_{N},$ respectively. We also find the mass and magnetic moment of ${T}_{\mathrm{bb}}^{-}$ as ${M}_{{T}_{\mathrm{bb}}^{-}}=10338\phantom{\rule{3.33333pt}{0ex}}\text{MeV}$ and $\mu =-0.32{\mu }_{N},$ respectively. We find some bound state candidates of doubly heavy tetraquark systems with $I\left({J}^{P}\right)=0{\left(1\right)}^{+}$ $nn\overline{b}\overline{b},$ $I\left({J}^{P}\right)=0{\left(0\right)}^{+}$ $nn\overline{c}\overline{b},$ $I\left({J}^{P}\right)=0{\left(1\right)}^{+}$ $nn\overline{c}\overline{b},$ and $I\left({J}^{P}\right)=1/2{\left(1\right)}^{+}$ $ns\overline{b}\overline{b}.$ We compare our results with other approaches in the literature.