Implications of the evidence for direct $\mathbf{CP}$ violation in $D\to π^+π^-$ decays
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arXiv
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| Autori principali: | , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866917465479446528 |
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| author | Sinha, Rahul Browder, Thomas E. Deshpande, N. G. Sahoo, Dibyakrupa Sinha, Nita |
| author_facet | Sinha, Rahul Browder, Thomas E. Deshpande, N. G. Sahoo, Dibyakrupa Sinha, Nita |
| contents | The observation of $CP$ violation in the difference of $CP$ asymmetries between $D\to K^+K^-$ and $D\to π^+π^-$ has raised a debate whether the observed asymmetries can be regarded as a signal of physics beyond the standard model (SM). In this paper we obtain all the topological amplitudes and isospin amplitudes directly from measured observables for $D\to ππ$. These results unambiguously imply a very large penguin contribution, having a central value $4.74$ times the magnitude of the amplitude for $D^0\toπ^+ π^-$. This fitted central value differs from a reasonable SM estimate of $10\%$ with a significance greater than $3.3σ$. In contrast to previous studies, we present model-independent arguments based only on unitarity of re-scattering amplitudes to show that large penguins cannot arise from re-scattering alone and likely indicate physics beyond the SM. In a model-independent approach we show how a very small contribution from physics beyond the SM with a large weak phase alleviates the problem. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2505_24338 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Implications of the evidence for direct $\mathbf{CP}$ violation in $D\to π^+π^-$ decays Sinha, Rahul Browder, Thomas E. Deshpande, N. G. Sahoo, Dibyakrupa Sinha, Nita High Energy Physics - Phenomenology High Energy Physics - Experiment The observation of $CP$ violation in the difference of $CP$ asymmetries between $D\to K^+K^-$ and $D\to π^+π^-$ has raised a debate whether the observed asymmetries can be regarded as a signal of physics beyond the standard model (SM). In this paper we obtain all the topological amplitudes and isospin amplitudes directly from measured observables for $D\to ππ$. These results unambiguously imply a very large penguin contribution, having a central value $4.74$ times the magnitude of the amplitude for $D^0\toπ^+ π^-$. This fitted central value differs from a reasonable SM estimate of $10\%$ with a significance greater than $3.3σ$. In contrast to previous studies, we present model-independent arguments based only on unitarity of re-scattering amplitudes to show that large penguins cannot arise from re-scattering alone and likely indicate physics beyond the SM. In a model-independent approach we show how a very small contribution from physics beyond the SM with a large weak phase alleviates the problem. |
| title | Implications of the evidence for direct $\mathbf{CP}$ violation in $D\to π^+π^-$ decays |
| topic | High Energy Physics - Phenomenology High Energy Physics - Experiment |
| url | https://arxiv.org/abs/2505.24338 |