CMS-PAS-HIN-21-014

CMS-PAS-HIN-21-014
Constraining bottom quark energy loss and hadronization with B $^{+}$ and B $^{0}_{\mathrm{s}}$ nuclear modification factors in pp and PbPb collisions at 5.02 TeV with CMS
CMS Collaboration
18 September 2023

Abstract: The CMS Collaboration reports on the production yields of B $^{0}_{\mathrm{s}}$ and B $^{+}$ mesons in proton-proton (pp) collisions recorded in 2017 at the CERN LHC with a center-of-mass energy of 5.02 TeV. Utilizing an integrated luminosity of 302.3 pb $^{-1}$ , the analysis focuses on the exclusive decay channels $\mathrm{B}^0_{\mathrm{s}} \to \mathrm{J}/\psi (\mu^+\mu^-)\,\phi ({\mathrm{K}}^+ {\mathrm{K}}^-)$ and $\mathrm{B}^+ \to \mathrm{J}/\psi (\mu^+\mu^-)\,\mathrm{K}^{+}$ in a transverse momentum ( $p_{\mathrm{T}}$ ) range of 7-50 GeV/ $c$ and a rapidity interval $\|y\| < 2.4$ . The measured $p_{\mathrm{T}}$ -differential cross sections of B $^{+}$ and B $^{0}_{\mathrm{s}}$ in pp collisions are well-described by fixed-order plus next-to-leading logarithm calculations. Combining with the previous measurements in lead-lead collisions at the same center of mass, we measure the nuclear modification factor, $R_{\mathrm{AA}}$ , of the B $^{+}$ mesons. The $R_{\mathrm{AA}}$ of B $^{+}$ is significantly lower than unity, while B $^{0}_{\mathrm{s}}$ data hint at a larger $R_{\mathrm{AA}}$ than that of B $^{+}$ . The B $^{+}$ $R_{\mathrm{AA}}$ is compatible with the $R_{\mathrm{AA}}$ of charged hadrons and D $^0$ mesons in the intermediate $p_{\mathrm{T}}$ region, while a hint of a smaller suppression is observed for $p_{\mathrm{T}} <$ 10 GeV/ $c$ . The $R_{\mathrm{AA}}$ data from B $^{+}$ and B $^{0}_{\mathrm{s}}$ are also compared to theoretical calculations, providing constraints on the mechanism of beauty quark energy loss and hadronization in the quark-gluon plasma.
Links: CDS record (PDF) ; CADI line (restricted) ; These preliminary results are superseded in this paper, Submitted to JHEP. The superseded preliminary plots can be found here.

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