$τ^- \to π^- ην_τ$ decay induced by QED one-loop effects
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arXiv
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| Format: | Preprint |
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2023
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| _version_ | 1866929235482902528 |
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| author | Hernández-Tomé, Gerardo Castro, Gabriel López Portillo-Sánchez, Diego |
| author_facet | Hernández-Tomé, Gerardo Castro, Gabriel López Portillo-Sánchez, Diego |
| contents | The $τ^- \to π^-ην_τ$ decay is forbidden in the Standard Model in the limit of exact $G$-parity, it becomes a rare decay due to isospin symmetry breaking and it is very sensitive to the effects of effective scalar interactions. Since the parameters driving isospin breaking, $(m_d-m_u)/(m_s-\bar{m})$ and $α$, are of the same order, one may expect their $G$-parity breaking effects in this decay can be of similar magnitudes. In this work, we evaluate the effects of isospin-breaking amplitudes originated from a virtual photon at one-loop in a resonance dominance model to describe photon-hadron interactions. We find that these effects can shift the leading SM predictions based on the $u-d$ quark mass difference by roughly $12\%$, and should be taken into consideration in a precision comparison of theory and experiment in order to draw meaningful conclusions on New Physics. The effects in the rate of the analogous $τ^- \to π^-η'ν_τ$ decay can be larger ($\sim$ $78\%$), under the approximations assumed in this model. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2308_08067 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | $τ^- \to π^- ην_τ$ decay induced by QED one-loop effects Hernández-Tomé, Gerardo Castro, Gabriel López Portillo-Sánchez, Diego High Energy Physics - Phenomenology The $τ^- \to π^-ην_τ$ decay is forbidden in the Standard Model in the limit of exact $G$-parity, it becomes a rare decay due to isospin symmetry breaking and it is very sensitive to the effects of effective scalar interactions. Since the parameters driving isospin breaking, $(m_d-m_u)/(m_s-\bar{m})$ and $α$, are of the same order, one may expect their $G$-parity breaking effects in this decay can be of similar magnitudes. In this work, we evaluate the effects of isospin-breaking amplitudes originated from a virtual photon at one-loop in a resonance dominance model to describe photon-hadron interactions. We find that these effects can shift the leading SM predictions based on the $u-d$ quark mass difference by roughly $12\%$, and should be taken into consideration in a precision comparison of theory and experiment in order to draw meaningful conclusions on New Physics. The effects in the rate of the analogous $τ^- \to π^-η'ν_τ$ decay can be larger ($\sim$ $78\%$), under the approximations assumed in this model. |
| title | $τ^- \to π^- ην_τ$ decay induced by QED one-loop effects |
| topic | High Energy Physics - Phenomenology |
| url | https://arxiv.org/abs/2308.08067 |