Studies of beauty suppression via nonprompt D$^0$ mesons in PbPb collisions at $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV

TL;DR

This study measures the suppression of nonprompt D$^0$ mesons from b hadron decays in PbPb collisions at 5.02 TeV, revealing insights into beauty quark energy loss in quark-gluon plasma.

Contribution

First measurement of nonprompt D$^0$ meson spectra from b hadron decays in PbPb collisions at 5.02 TeV, providing new data on beauty quark suppression in quark-gluon plasma.

Findings

B $ o$ D$^0$ yield is suppressed in PbPb compared to pp.

Suppression weaker than prompt D$^0$ mesons and charged hadrons at ~10 GeV/c.

Indication of larger suppression than models predict at 2-5 GeV/c.

Abstract

The transverse momentum spectra of D$^0$ mesons from b hadron decays are measured at midrapidity ($|y|$ $<$ $1$) in pp and PbPb collisions at a nucleon-nucleon center of mass energy of 5.02 TeV with the CMS detector at the LHC. The D$^0$ mesons from b hadron decays are distinguished from prompt D$^0$ mesons by their decay topologies. In PbPb collisions, the B $\to$ D$^0$ yield is found to be suppressed in the measured $p_\mathrm{T}$ range from 2 to 100 GeV$/c$ as compared to pp collisions. The suppression is weaker than that of prompt D$^0$ mesons and charged hadrons for $p_\mathrm{T}$ around 10 GeV$/c$. While theoretical calculations incorporating partonic energy loss in the quark-gluon plasma can successfully describe the measured B $\to$ D$^0$ suppression at higher $p_\mathrm{T}$, the data show an indication of larger suppression than the model predictions in the range of 2 $\lt$ $p_\mathrm{T}$ $\lt$ 5 GeV$/c$.