Masses and decay constants of bound states containing fourth family quarks from QCD sum rules

TL;DR

This paper uses QCD sum rules to calculate the masses and decay constants of mesons containing hypothetical fourth-generation quarks, extending known results for bottom and charm quarkonia.

Contribution

It provides the first detailed QCD sum rule calculations for mesons with fourth-generation quarks, including nonperturbative effects from gluon condensates.

Findings

Masses and decay constants of fourth-generation mesons are estimated.

Results reduce to known bottom and charm meson properties when replacing fourth-generation quarks.

The study offers predictions for properties of hypothetical fourth-family hadrons.

Abstract

The heavy fourth generation of quarks that have sufficiently small mixing with the three known SM families form hadrons. In the present work, we calculate the masses and decay constants of mesons containing either both quarks from the fourth generation or one from fourth family and the other from known third family SM quarks in the framework of the QCD sum rules. In the calculations, we take into account two gluon condensate diagrams as nonperturbative contributions. The obtained results reduce to the known masses and decay constants of the $\bar b b$ and $\bar c c$ quarkonia when the fourth family quark is replaced by the bottom or charm quark.