Charmed Tetraquarks Tcc and Tcs from Dynamical Lattice QCD Simulations

Understand

Charmed tetraquarks $T_{cc}=(cc\bar{u}\bar{d})$ and $T_{cs}=(cs\bar{u}\bar{d})$ are studied through the S-wave meson-meson interactions, $D$-$D$, $\bar{K}$-$D$, $D$-$D^{*}$ and $\bar{K}$-$D^{*}$, on the basis of the (2+1)-flavor lattice QCD simulations with the pion mass $m_{\pi} \simeq $410, 570 and 700 MeV.

• For the charm quark, the relativistic heavy quark action is employed to treat its dynamics on the lattice.
• Using the HAL QCD method, we extract the S-wave potentials in lattice QCD simulations, from which the meson-meson scattering phase shifts are calculated.
• The phase shifts in the isospin triplet ($I$=1) channels indicate repulsive interactions, while those in the $I=0$ channels suggest attraction, growing as $m_{\pi}$ decreases.