Multi-fermion states for heavy fermions bound via Higgs exchange

TL;DR

This paper investigates the theoretical possibility of bound states of multiple heavy fermions via Higgs exchange, finding such states unlikely for known fermion masses but potentially feasible with hypothetical heavier fermions.

Contribution

It provides a relativistic mean field approximation analysis of multi-fermion bound states and estimates the critical fermion mass needed for their existence.

Findings

Bound states of 12 fermions are unlikely below certain mass thresholds.

Critical fermion mass for bound states is estimated between 320 and 410 GeV/c^2.

No bound state is expected for 12 top quarks with current fermion masses.

Abstract

A possibility to produce bound states of several heavy fermions, which are bound together due to the Higgs exchange, is examined. It is shown that for 12 fermions, 6 fermions and 6 antifermions, occupying the lowest S_{1/2} shell this bound state cannot exist if the fermion mass is below the critical value, which depends on the Higgs mass and is found to be restricted to 320 < m_{cr} < 410 Gev/c^2 for the Higgs mass in the interval 100 < m_{H}< 200 Gev/c^2. This estimate is derived in the relativistic mean field approximation. The corrections are estimated to be not able to reduce significantly the critical value for the fermion mass. Consequently there exist no bound state for 12 top quarks, and the only feasible hope to observe a bag of 12 fermions experimentally should rely on possible existence of heavy fermions of the next, fourth generations.