YSF Measurement of the shape of the $\mathrm{b}$ quark fragmentation function using charmed mesons produced inside $\mathrm{b}$ jets from $\mathrm{t}\overline{\mathrm{t}}$ decays

Abstract

A first measurement of the $\mathrm{b}$ quark fragmentation function at the LHC is presented. Charmed meson candidates produced via semi-leptonic $\mathrm{t}\overline{\mathrm{t}}$ decays ($\mathrm{t}\to \mathrm{bW}\to$ b-jet $\ell \nu$) are used as a proxy for the parent $\mathrm{B}$ meson. Templates are generated at various values of the fragmentation shape parameter $r_{\mathrm{b}}$, and are fit to the data to measure the value of $r_{\mathrm{b}}$. The final fit result is $r_{\mathrm{b}}=0.855\pm 0.037(\mathrm{stat})\pm 0.031(\mathrm{syst})$. This is the first measurement of the $\mathrm{b}$ quark fragmentation function within a color rich environment, and is consistent with previous results from $e^{+}{e}^{-}$ colliders.