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arXiv · 2110.07619

Enhancement of charm CP violation due to nearby resonances

Stefan Schacht·Amarjit Soni
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Abstract

Quantitative understanding of CP violation is extremely important as naturalness reasoning strongly suggests that new physics should be accompanied by beyond the Standard Model CP-odd phases. In 2019 LHCb made the first $5 σ$ discovery of CP violation in the charm system, leading to the new world average $Δa_{CP}^{\mathrm{dir}} = -0.00161 \pm 0.00028$. While some calculations have found this observation as requiring new physics, we suggest that scalar resonances nearby to $m_{D^0}$, in particular, $f_0(1710)$ and/or $f_0(1790)$ cause enhancements for CP violation within the SM. Thereby, our calculations based on the Standard Model suggest compatibility with the LHCb observations for now. However, experimental information especially on $f_0(1790)$ is rather sparse limiting our accuracy and further data on these resonances is strongly advocated.

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Stefan Schacht, Amarjit Soni. 2021-11-17. Enhancement of charm CP violation due to nearby resonances. https://doi.org/10.1016/j.physletb.2021.136855

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