Two-pion exchange contributions for coupled-channel B^(*)B^(*) and B^(*) <span style=

Abstract

In the paper [Phys.Rev.D 99 (2019) 9, 094013] of V. Baru et al., the LO and incomplete NLO potentials were utilised to investigate the line shapes of Zb(10610) and Zb(10650) and their (yet to be discovered) spin partners. The spin partners of Z± b ’s are conventionally refereed to as WbJ ’s with quantum numbers JP C = 0⁺⁺, 1⁺⁺ and 2⁺⁺. <br> In this thesis, the full next-to-leading order calculations of the effective potentials of B^(*) <span style="text-decoration: overline;">B</span>^(*) &rarr; B^(*) <span style="text-decoration: overline;">B</span>^(*) and B^(*)B^(*) &rarr; B^(*)B^(*) are presented. The Feynman rules are constructed based on heavy meson chiral perturbation theory and effective potentials up to NLO are obtained. The subsequent effective potentials are partial wave decomposed into quantum numbers J^PC = 0⁺⁺, 1⁺⁺, 1^+- and 2⁺⁺. For the first time, we also present results for non-diagonal transition potentials between different channels. Our results deviate in some aspects from earlier calculations. Arguments are provided supporting that ours are correct.