Measurement of relative branching fractions of B decays to $\psi(2S)$ and $J/\psi$ mesons

TL;DR

This paper measures the relative branching fractions of B-meson decays into $Apsi(2S)$ and $J/Apsi$ mesons across three decay modes using LHCb data, providing precise ratios with detailed uncertainties.

Contribution

The study provides the first precise measurements of the ratios of B-meson decay branching fractions into $Apsi(2S)$ and $J/Apsi$ mesons for multiple decay channels.

Findings

Ratios of branching fractions are approximately 0.594, 0.476, and 0.489 for the three decay modes.

Uncertainties include statistical, systematic, and from $Apsi$ branching fraction ratios.

Results improve the precision of B-meson decay measurements.

Abstract

The relative rates of B-meson decays into $J/\psi$ and $\psi(2S)$ mesons are measured for the three decay modes in pp collisions recorded with the LHCb detector. The ratios of branching fractions ($\mathcal{B}$) are measured to be $\frac{\mathcal{B}(B^+ \to \psi(2S) K^+)}{\mathcal{B}(B^+ \to J/\psi K^+)} = 0.594 \pm 0.006 (stat) \pm 0.016 (syst) \pm 0.015 (R_{\psi})$, $\frac{\mathcal{B}(B^0 \to \psi(2S) K^{*0})}{\mathcal{B}(B^0 \to J/\psi K^{*0})} = 0.476 \pm 0.014 (stat) \pm 0.010 (syst) \pm 0.012\,(R_{\psi})$, $\frac{\mathcal{B}^{0}_{s}(B^0_s \to \psi(2S)\phi)}{\mathcal{B}(B^0_s \to J/\psi\phi)} = 0.489 \pm 0.026 (stat) \pm 0.021 (syst) \pm 0.012\,(R_{\psi})$ where the third uncertainty is from the ratio of the $\psi(2S)$ and $J/\psi$ branching fractions to $\mu\mu$.