Hartree-Fock all-heavy $c$, $b$ multiquarks and constraints on new top-sector physics

TL;DR

This paper uses the Hartree-Fock approximation to study all-heavy quark multiquark states, including top quarks, and concludes that such states are unlikely to be bound within the Standard Model, providing constraints on new physics.

Contribution

It extends previous analyses of heavy multiquark states to include top quarks and NLO QCD effects, offering new constraints on potential new physics interactions.

Findings

No bound all-heavy multiquark states are expected in the Standard Model.

NLO QCD potential does not enable binding of top-quark multiquark states.

Experimental searches for these states can constrain new physics beyond the Standard Model.

Abstract

We deploy the Hartree-Fock approximation for all-heavy quark hadrons, including quarkonium, baryons, tetraquarks, pentaquarks, dibaryons and up to the 12-body dibaryon-antidibaryon which completely fill the $1s$ orbital, in a unified manner, with the spinless LO Coulomb interaction and beyond. After treating the $c$ and $b$ quarks in various combinations, we delve a bit longer on $t$-quark bound states. We extend the negative result of Kuchiev, Flambaum and Shuryak on the 12-body topball to now include the NLO QCD potential. We find that none of the examined multitop states should have binding energy exceeding their width in the Standard Model. Additional new-physics interactions can then be constrained by experimental searches for these bound states, assuming they are not detected, at a level somewhat less stringent than standing HEFT bounds, but with different systematics.