Charmoniumlike channels 1+ with isospin 1 from lattice and effective field theory

Many exotic charmoniumlike mesons have already been discovered experimentally, of which the Z(c) mesons with isospin 1 are prominent examples. We investigate J(PC) = 1(++/-) states with flavor c(-)cq(-)q(q=u, d) in isospin 1 using lattice QCD. This is the first study of these mesons employing more than one volume and involving frames with nonzero total momentum. We utilize two N-f =2 +1 CLS ensembles with m(pi) similar or equal to 280 MeV. The simulations are performed with unphysical light quark masses at a single lattice spacing of a similar or equal to 0.086 fm and omit psi(2S)pi, psi(3770)pi and three-particle decay channels, so our results provide only qualitative insights. Resulting eigenenergies are compatible or just slightly shifted down with respect to noninteracting energies, where the most significant shifts occur for certain D (D) over bar* states. Both channels 1(++/-) have a virtual pole slightly below the threshold if D (D) over bar* is assumed to be decoupled from other channels. In addition, we perform a coupled channel analysis of J/psi pi and D (D) over bar* scattering with J(PC) =1(+-) within an effective field theory framework. The J/psi pi and D (D) over bar* invariant-mass distributions from BESIII and finite-volume energies from several lattice QCD simulations, including this work, are fitted simultaneously. All fits yield two poles relatively close to the D (D) over bar* threshold and reasonably reproduce the experimental Z(c) peaks. They also reproduce lattice energies up to slightly above the D (D) over bar* threshold, while reproduction at even higher energies is better for fits that put more weight on the lattice data. Our findings suggest that the employed effective field theory can reasonably reconcile the peaks in the experimental line shapes and the lattice energies, although those lie close to noninteracting energies. We also study J/psi pi scattering in s wave and place upper bounds on the phase shift.