Meson Spectroscopy without Tetraquarks

TL;DR

This paper challenges the tetraquark interpretation of certain bottomonium decay data, proposing that these phenomena can be explained by conventional quark-antiquark states and meson interactions.

Contribution

It offers an alternative explanation to the tetraquark hypothesis for Upsilon decay enhancements, emphasizing conventional meson and quark-antiquark states.

Findings

Data can be explained without tetraquarks using meson interactions.

Open-b threshold processes account for observed decay patterns.

Charm sector peaks may be due to regular c-cbar states, not exotic states.

Abstract

Data on e+e- -> piplus-piminus-Upsilon(1S,2S,3S) show a large increase in branching fractions near Upsilon(10860). A suggestion of Ali et al. is to interpret this as evidence for a tetraquark, Yb(10890) = b-bbar. However, it may also be interpreted in terms of Upsilon(10860) -> B-B*, B*B* and BsB*s above the open-b threshold, followed by de-excitation processes such as $BB* -> Upsilon (1S,2S,3S). In the charm sector, a hypothesis open to experimental test is that X,Y and Z peaks in the mass range 3872 to 3945 MeV may all be due to regular 3P1 and 3P2 c-cbar states (and perhaps 3P0) mixed with meson-meson.