A diffusion Monte Carlo calculation of fully heavy pentaquarks

TL;DR

This paper uses diffusion Monte Carlo to calculate the spectra of fully heavy pentaquarks, revealing that molecular configurations are nearly as stable as compact ones, making them promising candidates for experimental detection.

Contribution

First application of diffusion Monte Carlo to compute spectra of fully heavy pentaquarks within the quark model framework, comparing different spin-color configurations.

Findings

Molecular configurations have lower masses than symmetric counterparts.

Most molecular states are unstable but have small excess masses (~20-60 MeV).

Compact molecular structures are promising for experimental detection.

Abstract

Using a diffusion Monte Carlo algorithm, we calculated the spectra of all possible $S$-wave fully heavy pentaquarks within the framework of the quark model. Our aim was to compare the masses of different spin-color configurations corresponding to the same spatial wavefunction for each quark composition. In particular, we computed the masses of the configuration with the maximum number of undistinguishable quarks and those of all the possible baryon+meson splittings compatible with the total number of $b$'s and $c$'s for a given pentaquark. What we found was that, in all cases, compact baryon+meson configurations had lower masses than their more symmetric counterparts. Moreover, those "molecular" associations were unstable (with larger masses) that their infinitely separated non-interacting pieces except int the case of $(ccb)(c\bar{b})$ and $(bbc)(b\bar{c})$ pentaquarks. In any case, even for unstable arrangements, the excess masses are so small ($\sim$20-60 MeV) as to make those compact molecular structures serious candidates to be experimentally detected.