Heavy-quark exotics

TL;DR

This paper reviews recent theoretical and experimental advances in heavy-quark exotic states, including molecules, baryons, tetraquarks, and excited states involving charm and bottom quarks.

Contribution

It provides a comprehensive overview of the properties, stability, and spectra of heavy-quark exotics, highlighting new findings and ongoing research in the field.

Findings

Observation of stable tetraquarks under strong decay

First measurements of doubly charmed baryon masses and lifetimes

Identification of excited $ ext{Omega}_c$ states

Abstract

The heavy quarks $c$ and $b$ stabilize exotic meson $(qq\bar q \bar q)$ and baryon $(qqqq \bar q)$ states. We discuss work with M. Karliner on molecules containing $c \bar c$ and $b \bar b$; the first doubly charmed baryon; isospin splittings; $\Xi_{cc}^+ = ccd$ and $\Omega_{cc} = ccs$ masses; lifetimes; tetraquarks stable under strong and electromagnetic decay; excited $\Omega_{c}$ states; and P-wave excitation energies.