Some hadronic parameters of charmonia in $\boldsymbol{N_{\text{f}}=2}$ lattice QCD

TL;DR

This paper presents a lattice QCD study of decay constants for charmonium states, providing insights into their properties and potential implications for beyond Standard Model physics.

Contribution

It reports new lattice QCD calculations of decay constants for $ ext{N}_f=2$ charmonium states, including excited states, which were previously less understood.

Findings

Calculated decay constants for $ ext{N}_f=2$ $ ext{J}/ ext{psi}$ and $ ext{$ ext{eta}_c$}$.

Examined properties of first radial excitations $ ext{$ ext{eta}_c(2S)$}$ and $ ext{$ ext{psi}(2S)$}$.

Results can constrain new physics scenarios involving light CP-odd states.

Abstract

The phenomenology of leptonic decays of quarkonia holds many interesting features: for instance, it can establish constraints on scenarios beyond the Standard Model with the Higgs sector enriched by a light CP-odd state. In the following paper, we report on a two-flavor lattice QCD study of the $\eta_c$ and $J/\psi$ decay constants, $f_{\eta_c}$ and $f_{J\psi}$. We also examine some properties of the first radial excitation $\eta_c(2S)$ and $\psi(2S)$.