Probing light pseudoscalar, axial vector states through $\eta_{b} \to\tau^{+}\tau^{-}$

TL;DR

This paper investigates the decay of eta_b into tau pairs as a way to detect light pseudoscalar or axial vector particles, showing potential for larger-than-Standard Model decay rates in new physics models.

Contribution

It provides estimates of decay branching ratios in the Standard Model and explores how new light states could significantly enhance these rates.

Findings

Standard Model branching ratio ~4×10^{-9}

Possible branching ratios up to 8% in new physics models

Results are reliable away from pseudoscalar-eta_b mixing regions

Abstract

In this paper we explore the decay $\eta_b --> \tau^+ \tau^-$ as a probe for a light pseudoscalar or a light axial vector state. We estimate the standard model branching ratio for this decay to be $~4\times 10^{-9}$. We show that considerably larger branching ratios, up to the present experimental limit of ~8%, is possible in models with a light pseudoscalar or a light axial vector state. As we do not include possible mixing effects between the light pseudoscalar and the $\eta_b$, our results should be reliable when the pseudoscalar mass is away from the $\eta_b$ mass.