# Fully Heavy Tetraquark ${bb \bar c \bar c}$: Lifetimes and Weak Decays

## TL;DR

This paper investigates the lifetime and decay modes of a fully heavy tetraquark with two bottom and two charm quarks, providing theoretical predictions to aid future experimental searches.

## Contribution

It presents the first comprehensive analysis of the lifetime and decay channels of the ${bb ar c ar c}$ tetraquark using heavy quark expansion and flavor symmetry methods.

## Key findings

- Estimated lifetime of (0.1-0.3)×10^{-12}s.
- Identified key decay channels such as $T_{ar c ar c}^{bb} o B^- K^0 B_c^-$.
- Provided relations between decay widths of different modes.

## Abstract

We study the lifetime and weak decays of the full-heavy S-wave $0^+$ tetraquark $T^{\{bb\}}_{\{\bar c\bar c\}}$. Using the operator product expansion rooted in heavy quark expansion, we find a rather short lifetime, at the order $(0.1-0.3)\times 10^{-12}s$ depending on the inputs. With the flavor SU(3) symmetry, we then construct the effective Hamiltonian at the hadron level, and derive relations between decay widths of different channels. According to the electro-weak effective operators, we classify different decay modes, and make a collection of the golden channels, such as $T_{\{\bar c \bar c\}}^{\{bb\}}\to B^- K^0 B_c^-$ for the charm quark decay and $T_{\{\bar c \bar c\}}^{\{bb\}}\to B^-D^-$ for the bottom quark decay. Our results for the lifetime and golden channels are helpful to search for the fully-heavy tetraquark in future experiments.