Effects of hadronic loops on the direct CP violation of $B_{c}$

TL;DR

This paper investigates how hadronic loops and final state interactions influence direct CP violation in Bc meson decays, highlighting their significant impact on CP asymmetry measurements crucial for new physics searches.

Contribution

It provides a quantitative analysis of the impact of hadronic loops on CP violation in Bc decays, emphasizing the importance of including final state interactions in experimental data interpretation.

Findings

CP asymmetry can reach about -22% with final state interactions

Final state interactions significantly alter CP violation predictions

Including FSI is crucial for accurate CP violation analysis in Bc decays

Abstract

It is well known that the final state interaction plays an important role in the decays of $B$-meson. The contribution of the final state interaction which is supposed to be long-distance effects, to the concerned processes can interfere with that of the short-distance effects produced via the tree and/or loop diagrams at quark-gluon level. The interference may provide a source for the direct CP violation $\mathcal{A}_{CP}$ in the process $B_{c}^{+}\to D^{0}\pi^{+}$. We find that a typical value of $\mathcal{A}_{CP}$ when the final state interaction effect is taken into account can be about -22% which is different from that without the final state interaction effect. Therefore, when we extract information on CP violation from the data which will be available at LHCb and the new experiments in $B$-factories, the contribution from the final state interaction must be included. This study may be crucial for searching new physics in the future.