Heavy light tetraquarks from Lattice QCD

Understand

We present preliminary results from a lattice calculation of tetraquark states in the charm and bottom sector of the type $ud\bar{b}\bar{b}$, $us\bar{b}\bar{b}$, $ud\bar{c}\bar{c}$ and $sc\bar{b}\bar{b}$.

• These calculations are performed on $N_f = 2 + 1 + 1$ MILC ensembles with lattice spacing of $a = 0.12~\mathrm{fm} $ and $a=0.06~\mathrm{fm} $.
• A relativistic action with overlap fermions is employed for the light and charm quarks while a non-relativistic action with non-perturbatively improved coefficients is used in the bottom sector.
• Preliminary results provide a clear indication of presence of energy levels below the relevant thresholds of different tetraquark states.