Bogotá - Ciencias - Maestría en Ciencias - Física · 2026

Search for Bc± -> ϕK± in the LHCb experiment

A search for the rare annihilation decay $B_c^{\pm} \rightarrow \phi K^{\pm}$ is performed using proton-proton collision data collected by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb$^{-1}$. No significant signal is observed, and upper limits on the ratio of branching fractions relative to the normalization channel $B^{\pm} \rightarrow \phi K^{\pm}$ and on the absolute branching fraction are set at the 95\% confidence level: \begin{equation*} \frac{BR(B_c^{\pm} \rightarrow \phi K^{\pm})}{BR(B^{\pm} \rightarrow \phi K^{\pm})} < \text{\Rupper} \quad \text{and} \quad BR(B_c^{\pm} \rightarrow \phi K^{\pm}) < \text{\BrBcupper}. \end{equation*} The branching fraction of the normalization channel is measured to be \begin{equation*} BR(B^{\pm} \rightarrow \phi K^{\pm}) = (9.46 \pm 0.06 \pm 0.63 \pm 0.71) \times 10^{-6}, \end{equation*} where the first uncertainty is statistical, the second systematic, and the third due to external inputs. This result is consistent with the current world average.