Tcc in the diabatic diquark model: Effects of D*D isospin

Abstract

Tcc+ is an isoscalar 4-quark state with mass lying barely below the D*+D0 threshold, and several times further below the D*0D+ threshold. It allows both dimeson molecular and elementary diquark-antidiquark (cc)(u¯d¯) substructures. The diabatic generalization of the adiabatic approximation within the Born-Oppenheimer formalism rigorously incorporates the mixing of such elementary eigenstates with states corresponding to two-particle thresholds. We examine the separate influence of the two D*D isospin channels and find that the influence of D*+D0 is larger than that of D*0D+ but not overwhelmingly so, and that Tcc+ contains an O(10%) (cc)(u¯d¯) component. We then explore the variation of these results if the isospin breaking between the dimeson thresholds is varied, and also the sensitivity of our results to variation of the mixing-potential parameters. Published by the American Physical Society 2024