# Radiative decays and the $\mathbf {SU(6)}$ Lie Algebra

## TL;DR

This paper investigates radiative decays of vector mesons to pseudoscalar mesons using $SU(6)$ Lie algebra and symmetry techniques, revealing the crucial role of the electromagnetic current singlet in these processes.

## Contribution

It introduces new relations involving the electromagnetic current within the $SU(6)$ framework and highlights the singlet's role in radiative decays, without assuming specific meson quark structures.

## Key findings

- Electromagnetic current singlet is key in radiative decays.
- Derived all $SU(6)$ roots, weights, and generator relations.
- Parametrized predictions for unmeasured decay widths.

## Abstract

We present research on radiative decays of vector ($J^{PC}=1^{--}$) to pseudoscalar ($J^{PC}=0^{-+}$) particles ($u$, $d$, $s$, $c$, $b$, $t$ quark system) using broken symmetry techniques in the infinite momentum frame and equal time commutation relations and the $SU(6)$ Lie algebra and conducted without ascribing any specific form to meson quark structure or intra-quark interactions. We utilize the physical electromagnetic current $j_{em}^{\mu}(0)$ including its singlet $U(1)$ term and focus on the $SU(6)$ $35$-plet. We derive new relations involving the electromagnetic current (including its singlet--proportional to the $SU(6)$ singlet). Remarkably, we find that the electromagnetic current singlet plays an intrinsic role in understanding the physics of radiative decays and that the charged and neutral $\rho$ meson radiative decays into $\pi \, \gamma$ are due entirely to the singlet term in $j_{em}^{\mu}(0)$. Although there is insufficient radiative decay experimental data available at this time, parametrization of possible predicted values of $\Gamma({{{D}}^{*}}^{0}\rightarrow D^{0}\,\gamma)$ is made. For conciseness and self-containment, we compute all $SU(6)$ Lie algebra simple roots, positive roots, weights and fundamental weights which allow the construction of all $SU(6)$ representations. We also derive all non-zero $SU(6)$ generator commutators and anti-commutators---useful for further research on grand unified theories.

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Source: https://tomesphere.com/paper/1902.00853