On the decay of a light spinless particle into two photons
Fuente:
arXiv
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| Autori principali: | , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866914217937862656 |
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| author | Feruglio, Ferruccio Levati, Gabriele Ziegler, Robert |
| author_facet | Feruglio, Ferruccio Levati, Gabriele Ziegler, Robert |
| contents | We analyze the effective couplings of a light, spinless, gauge-singlet particle $ϕ$ to on-shell photons. Starting from the most general theory at the electroweak scale, which allows for CP-violating interactions suppressed by inverse powers of an ultraviolet scale $Λ$, we derive the corresponding low-energy effective theory valid below the GeV scale. Within this framework, we systematically expand the effective couplings of $ϕ$ to on-shell photons in powers of small parameters. Working at the one-loop level, we retain terms at first order in $1/Λ$. We incorporate both isospin-breaking effects and $η$-$η'$ mixing, and provide explicit expressions for the couplings up to first order in $m_ϕ^2/m_η^2$ and $m_π^2/m_η^2$. As applications, we compute the decay rate of $ϕ$ into two photons and illustrate our results in several physically motivated scenarios. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_20695 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | On the decay of a light spinless particle into two photons Feruglio, Ferruccio Levati, Gabriele Ziegler, Robert High Energy Physics - Phenomenology We analyze the effective couplings of a light, spinless, gauge-singlet particle $ϕ$ to on-shell photons. Starting from the most general theory at the electroweak scale, which allows for CP-violating interactions suppressed by inverse powers of an ultraviolet scale $Λ$, we derive the corresponding low-energy effective theory valid below the GeV scale. Within this framework, we systematically expand the effective couplings of $ϕ$ to on-shell photons in powers of small parameters. Working at the one-loop level, we retain terms at first order in $1/Λ$. We incorporate both isospin-breaking effects and $η$-$η'$ mixing, and provide explicit expressions for the couplings up to first order in $m_ϕ^2/m_η^2$ and $m_π^2/m_η^2$. As applications, we compute the decay rate of $ϕ$ into two photons and illustrate our results in several physically motivated scenarios. |
| title | On the decay of a light spinless particle into two photons |
| topic | High Energy Physics - Phenomenology |
| url | https://arxiv.org/abs/2512.20695 |