Strong decays of the lowest bottomonium hybrid within an extended Born\u2013Oppenheimer framework

Abstract

We analyze the decays of the theoretically predicted lowest bottomonium hybrid H(1P) to open bottom two-meson states. We do it by embedding a quark pair creation model into the Born–Oppenheimer framework which allows for a unified, QCD-motivated description of bottomonium hybrids as well as bottomonium. A new ^{1}!P_{1} decay model for H(1P) comes out. The same analysis applied to bottomonium leads naturally to the well-known ^{3}!P_{0} decay model. We show that H(1P) and the theoretically predicted bottomonium state varUpsilon (5S), whose calculated masses are close to each other, have very different widths for such decays. A comparison with data from varUpsilon (10860), an experimental resonance whose mass is similar to that of varUpsilon (5S) and H(1P), is carried out. Neither a varUpsilon (5S) nor a H(1P) assignment can explain the measured decay widths. However, a varUpsilon (5S)–H(1P) mixing may give account of them supporting previous analyses of dipion decays of varUpsilon (10860) and suggesting a possible experimental evidence of H(1P).