New Exotic Meson and Baryon Resonances from Doubly-Heavy Hadronic Molecules

Abstract

We predict several new exotic doubly-heavy hadronic resonances, inferring from the observed exotic bottomonium-like and charmonium-like narrow states $X(3872)$, $Z_b(10610)$, $Z_b(10650)$, $Z_c(3900)$, and $Z_c(4020/4025)$. We interpret the binding mechanism as mostly molecular-like isospin-exchange attraction between two heavy-light mesons in a relative S-wave state. We then generalize it to other systems containing two heavy hadrons which can couple through isospin exchange. The new predicted states include resonances in meson-meson, meson-baryon, baryon-baryon, and baryon-antibaryon channels. These include those giving rise to final states involving a heavy quark $Q=c,b$ and antiquark ${\bar{Q}}^{\prime }=\bar{c},\bar{b}$, namely $D{\bar{D}}^{\ast }$, $D^{\ast }{\bar{D}}^{\ast }$, $D^{\ast }{B}^{\ast }$, $\bar{B}{B}^{\ast }$, ${\bar{B}}^{\ast }{B}^{\ast }$, ${\Sigma }_c{\bar{D}}^{\ast }$, ${\Sigma }_c{B}^{\ast }$, ${\Sigma }_b{\bar{D}}^{\ast }$, ${\Sigma }_b{B}^{\ast }$, ${\Sigma }_c{\bar{\Sigma }}_c$, ${\Sigma }_c{\bar{\Lambda }}_c$, ${\Sigma }_c{\bar{\Lambda }}_b$, ${\Sigma }_b{\bar{\Sigma }}_b$, ${\Sigma }_b{\bar{\Lambda }}_b$, and ${\Sigma }_b{\bar{\Lambda }}_c$, as well as corresponding S-wave states giving rise to $Q{Q}^{\prime }$ or $\bar{Q}{\bar{Q}}^{\prime }$.

Comments: 8 pages, no figures, additional text and references, to be published in Phys. Rev. Letters