Masses and widths of the exotic molecular $B_{(s)}^{(*)} B_{(s)}^{(*)}$ states

TL;DR

This paper investigates the masses and widths of exotic doubly bottom molecular states using vector meson exchange and unitarized coupled-channel analysis, predicting several bound states with specific quantum numbers and their decay widths.

Contribution

It introduces a novel calculation of doubly bottom molecular states using an extended local hidden gauge approach with unitarity, predicting their masses, widths, and quantum numbers.

Findings

Identifies poles below thresholds for specific B meson combinations with J^P=1^+

Predicts binding energies of 10-20 MeV for these states

Finds widths ranging from eV to MeV depending on the system

Abstract

We study the interaction of the doubly bottom systems $BB$, $B^* B$, $B_s B$, $B_s^* B$, $B^* B^*$, $B^* B_s$, $B^*B_s^*$, $B_s B_s$, $B_s B_s^*$, $B_s^* B_s^*$ by means of vector meson exchange with Lagrangians from an extension of the local hidden gauge approach. The full s-wave scattering matrix is obtained implementing unitarity in coupled channels by means of the Bethe-Salpeter equation. We find poles below the channel thresholds for the attractively interacting channels $B^* B$ in $I=0$, $B^*_s B-B^*B_s$ in $I=\frac{1}{2}$, $B^* B^*$ in $I=0$, and $B^*_s B^*$ in $I=\frac{1}{2}$, all of them with $J^P=1^+$. For these cases the widths are evaluated identifyng the dominant source of imaginary part. We find binding energies of the order of $10-20$ MeV, and the widths vary much from one system to the other: of the order of 10-100 eV for the $B^* B$ system and $B^*_s B-B^*B_s$, about $6$ MeV for the $B^* B^*$ system and of the order of $0.5$ MeV for the $B^*_s B^*$ system.