Saved in:
| Main Authors: | , , |
|---|---|
| Format: | Preprint |
| Published: |
2025
|
| Subjects: | |
| Online Access: | https://arxiv.org/abs/2510.00787 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866908571812233216 |
|---|---|
| author | Escribano, Rafel Gonzàlez-Solís, Sergi Royo, Emilio |
| author_facet | Escribano, Rafel Gonzàlez-Solís, Sergi Royo, Emilio |
| contents | In light of the recent measurement of the $η\toπ^{0}γγ$ decay by the KLOE-2 Collaboration, a previous analysis including vector- and scalar-meson exchange contributions using the VMD and L$σ$M frameworks, respectively, is extended in the present study to incorporate the effects of the $a_{2}(1320)$ tensor meson within a chiral context. Although the individual contribution of the $a_{2}$ is negligible, its destructive interference with the vector-meson resonances is found to be significant, representing approximately $18\%$ of the total signal and substantially affecting the diphoton invariant-mass distribution, especially at low $m_{γγ}^{2}$ values. The total decay rate is calculated to be $Γ(η\toπ^{0}γγ)=0.154(22)$ eV, which corresponds to a branching ratio of ${\rm BR}(η\toπ^{0}γγ)=1.17(17)\times10^{-4}$. This result is approximately $5σ$ below the reported value of the PDG, $2.55(22)\times10^{-4}$, while it is in very good agreement with the KLOE-2 measurement, $0.98(11_{\rm stat})(14_{\rm syst})\times10^{-4}$. In contrast, the total contribution of the $a_{2}$ is found to be negligible in $η^{\prime}\toπ^{0}γγ$, as this process is completely dominated by the exchange of an on-shell $ω$ vector resonance. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2510_00787 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Assessment of the $a_{2}(1320)$ tensor-meson contribution to $η/η^{\prime}\toπ^{0}γγ$ decays Escribano, Rafel Gonzàlez-Solís, Sergi Royo, Emilio High Energy Physics - Phenomenology High Energy Physics - Experiment In light of the recent measurement of the $η\toπ^{0}γγ$ decay by the KLOE-2 Collaboration, a previous analysis including vector- and scalar-meson exchange contributions using the VMD and L$σ$M frameworks, respectively, is extended in the present study to incorporate the effects of the $a_{2}(1320)$ tensor meson within a chiral context. Although the individual contribution of the $a_{2}$ is negligible, its destructive interference with the vector-meson resonances is found to be significant, representing approximately $18\%$ of the total signal and substantially affecting the diphoton invariant-mass distribution, especially at low $m_{γγ}^{2}$ values. The total decay rate is calculated to be $Γ(η\toπ^{0}γγ)=0.154(22)$ eV, which corresponds to a branching ratio of ${\rm BR}(η\toπ^{0}γγ)=1.17(17)\times10^{-4}$. This result is approximately $5σ$ below the reported value of the PDG, $2.55(22)\times10^{-4}$, while it is in very good agreement with the KLOE-2 measurement, $0.98(11_{\rm stat})(14_{\rm syst})\times10^{-4}$. In contrast, the total contribution of the $a_{2}$ is found to be negligible in $η^{\prime}\toπ^{0}γγ$, as this process is completely dominated by the exchange of an on-shell $ω$ vector resonance. |
| title | Assessment of the $a_{2}(1320)$ tensor-meson contribution to $η/η^{\prime}\toπ^{0}γγ$ decays |
| topic | High Energy Physics - Phenomenology High Energy Physics - Experiment |
| url | https://arxiv.org/abs/2510.00787 |