Implications of Heavy Quark-Diquark Symmetry for Excited Doubly Heavy Baryons and Tetraquarks

TL;DR

This paper uses heavy quark-diquark symmetry to predict properties of excited doubly heavy baryons and tetraquarks, including decay behaviors and stability, based on recent experimental discoveries and theoretical models.

Contribution

It introduces a new Lagrangian for tetraquarks related to baryon Lagrangians, applying heavy quark-diquark symmetry to predict masses and decay widths of doubly heavy baryons and tetraquarks.

Findings

Predicted five excited doubly charm baryons below the $ ext{Lambda}_c D$ threshold.

Forecasted a stable doubly bottom tetraquark with mass below 10405 MeV.

Calculated decay widths for tetraquark states using a novel Lagrangian.

Abstract

We give heavy quark-diquark symmetry predictions for doubly heavy baryons and tetraquarks in light of the recent discovery of the $\Xi_{cc}^{++}$ by LHCb. For five excited doubly charm baryons that are predicted to lie below the $\Lambda_c D$ threshold, we give predictions for their electromagnetic and strong decays using a previously developed chiral Lagrangian with heavy quark-diquark symmetry. Based on the mass of the $\Xi_{cc}^{++}$, the existence of a doubly heavy bottom $I=0$ tetraquark that is stable to the strong and electromagnetic decays has been predicted. If the mass of this state is below 10405 MeV, as predicted in some models, we argue using heavy quark-diquark symmetry that the $J^P=1^+$ $I=1$ doubly bottom tetraquark state will lie just below the open bottom threshold and likely be a narrow state as well. In this scenario, we compute strong decay width for this state using a new Lagrangian for tetraquarks which is related to the singly heavy baryon Lagrangian by heavy quark-diquark symmetry.