Speaker
Description
The study of $CP$ violation is vital in unlocking new insights into the observed dominance of matter over antimatter in our universe. Electroweak penguin decays like $\bar{B}^0 \rightarrow \bar{K}^{*0} \mu^+\mu^-$ are of particular importance in this pursuit, as they are highly sensitive to $CP$ violation and/or new physics effects. To this end we performed a search for $CP$ violation in the $\bar{B}^0 \rightarrow \bar{K}^{*0} \mu^+\mu^-$ decay using 8.4fb$^{-1}$ of proton-proton collision data collected by the LHCb experiment during Run 1 and Run 2. By leveraging the full angular distribution of this decay, we are able to probe for $CP$-violating effects in both the vector and axial-vector contributions to the flavour-changing neutral-current process. The complex Wilson coefficients that quantify these different contributions in Weak Effective Theory are determined through an unbinned maximum-likelihood fit to the angular observables, incorporating nonlocal hadronic amplitudes across the full dimuon mass spectrum. The precision of the $CP$-violation observables is improved by an order of magnitude relative to previous measurements, with the imaginary parts of the Wilson coefficients now determined more precisely than the real parts. No significant $CP$ violation is observed, and the results are consistent with Standard Model.
| I am the presenting author | Yes |
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