Signature of a doubly charm tetraquark pole in $D{D}^{\ast }$ scattering on the lattice

Abstract

The doubly charm tetraquark with flavor $cc\bar{u}\bar{d}$ and isospin $I=0$ is investigated by calculating the $D{D}^{\ast }$ scattering amplitude with lattice QCD. The simulation is done on CLS ensembles with dynamical $u/d,s$ quarks and $m_{\pi }\simeq 280$MeV for two charm quark masses, one slightly larger and one slightly lower than the physical value. The scattering amplitudes for partial waves $l=0,1$ are extracted near-threshold via the Lüscher's method by considering systems with total momenta $PL/(2\pi )=0,1,\sqrt{2},2$ on two spatial volumes. A virtual bound state pole in the $D{D}^{\ast }$ scattering amplitude with $l=0$ is found $9.9_{-7.1}^{+3.6}$MeV below $D{D}^{\ast }$ threshold for the charm quark mass closer to the physical value. This pole is likely related to the doubly charm tetraquark discovered by LHCb less than $1$MeV below $D^0{D}^{\ast +}$ threshold. Future lattice simulations closer to the continuum limit and physical quark masses would be valuable to establish this connection systematically.

Comments: version to appear in Phys.Rev.Lett. 6(+6) pages; 4(+6) figures; 2(+1) tables; Modified and extended discussions, supplemental material and video file. Results and conclusions unchanged