Speaker
Description
At the large distances compared to the chiral symmetry breaking scale, a four-quark state $\bar Q \bar Q q q$ (with $Q$ as heavy and $q$ as light quarks) can be treated as two asymptotic mesons interacting via strong residual forces. To analyse the long-range strong force in such a system, we study the interaction between two bottom mesons in the heavy quark limit using chiral effective field theory and dispersion theory. In this contribution, methods to deal with the two-pion-exchange interaction between two static heavy mesons at non-physical pion mass will be discussed. A possible solution, where we use the Khuri-Treiman formalism to properly include the left- and right-hand cuts, will be presented. Finally, a comparison of the obtained results with the corresponding lattice QCD potentials (obtained using the Born-Oppenheimer approximation) will be made.
