CERN Accelerating science

CMS Note
Report number	CMS-CR-2022-017
Title	YSF Measurement of the shape of the $\mathrm{b}$ quark fragmentation function using charmed mesons produced inside $\mathrm{b}$ jets from $\mathrm{t\overline{t}}$ decays
Author(s)	Yates, Brent Robert (Ohio State U.)
Publication	2022
Collaboration	CMS Collaboration
Imprint	18 Jan 2022
Number of pages	7
Presented at	14th International Workshop on Top Quark Physics 2021, Online, Online, 13 - 17 Sep 2021
Subject category	Detectors and Experimental Techniques
Accelerator/Facility, Experiment	CERN LHC ; CMS
Keywords	General
Abstract	A first measurement of the $\mathrm{b}$ quark fragmentation function at the LHC is presented. Charmed meson candidates produced via semi-leptonic $\mathrm{t\overline{t}}$ decays ($\mathrm{t} \to \mathrm{b}\mathrm{W} \to$ 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.