The $b$ quark fragmentation fractions at LHCb and meson decays with heavy quark spectators

Abstract

We study the current estimates of $B_c\to B_s\pi$ to extract the fragmentation fraction $f_c/f_s$ at the LHCb. A rather robust estimate of $Br(B_c\to B_s\pi )$ based on factorization and lattice results for the form factor gives $f_c/f_s\sim 0.056$ with a $16\%$ error. We also revisit the extraction of $f_s/f_d$ using $B\to D\pi$ instead of the theoretical cleaner but more suppressed channel $B\to DK$. We also find a tension on the predictions of $Br(B_c\to J/\psi \pi )$ and $Br(B_c\to B_s\pi )$ considering the measurements of these modes at LHCb, and find that, within a $23\%$ uncertainty, only the lower end of the current prediction range $Br(B_c\to J/\psi )\sim 0.4\%-1.7\%$ would be consistent with the LHCb measurements.

11 pages, 2 figures

References in corpus (6)

• Exclusive semileptonic and nonleptonic decays of the Bc meson
• Precise measurement of the $f_s/f_d$ ratio of fragmentation fractions and of $B_s^0$ decay branching fractions
• A puzzle in ${\bar{B}}_{(s)}^0\to D_{(s)}^{(\ast )+}\{{\pi }^{-},K^{-}\}$ decays and extraction of the $f_s/f_d$ fragmentation fraction
• $B_c\to B_{s(d)}$ form factors from lattice QCD
• Exclusive nonleptonic Bc-meson decays to S-wave charmonium states
• Measurement of the branching fraction of the $B^0\to D_s^{+}{\pi }^{-}$ decay