The production yields of non-prompt $\mathrm{D_s}^{+}$ mesons, namely $\mathrm{D_s}^{+}$ mesons from beauty-hadron decays, were measured for the first time as a function of the transverse momentum ($p_{\rm T}$) at midrapidity ($|y|<~0.5$) in central and semi-central Pb$-$Pb collisions at a centre-of-mass energy per nucleon pair $\sqrt{s_{\rm NN}}=5.02$ TeV with the ALICE experiment at the LHC. The $\mathrm{D_s}^{+}$ mesons and their charge conjugates were reconstructed from the hadronic decay channel $\mathrm{D_s}^{+} \to \phi\pi^+$, with $\phi \to {\rm K}^-{\rm K}^+$, in the $4 <~ p_{\rm T}<~36$ GeV/$c$ and $2 <~ p_{\rm T}<~24$ GeV/$c$ intervals for the 0$-$10% and 30$-$50% centrality classes, respectively. The measured yields of non-prompt $\mathrm{D_s}^{+}$ mesons are compared to those of prompt $\mathrm{D_s}^{+}$ and non-prompt $\mathrm{D^0}$ mesons by calculating the ratios of the production yields in Pb$-$Pb collisions and the nuclear modification factor $R_\mathrm{AA}$. The ratio between the $R_\mathrm{AA}$ of non-prompt $\mathrm{D_s}^{+}$ and prompt $\mathrm{D_s}^{+}$ mesons, and that between the $R_\mathrm{AA}$ of non-prompt $\mathrm{D_s}^{+}$ and non-prompt $\mathrm{D^0}$ mesons in central Pb$-$Pb collisions are found to be on average higher than unity in the $4<~ p_{\rm T}<~12$ GeV/$c$ interval with a statistical significance of about $1.6\,\sigma$ and $1.7\,\sigma$, respectively. The measured $R_\mathrm{AA}$ ratios are compared with the predictions of theoretical models of heavy-quark transport in a hydrodynamically expanding QGP that incorporate hadronisation via quark recombination.
Phys. Lett. B 846 (2023) 137561
HEP Data
e-Print: arXiv:2204.10386 | PDF | inSPIRE
CERN-EP-2022-065
Figure group
Figure 1
Invariant mass distribution of non-prompt $\Ds$ candidates and their charge conjugates in the $4<\pt<6$ $\gevc$ interval for central Pb--Pb collisions. The blue solid line shows the total fit function and the red dashed line the combinatorial-background contribution. The values of the mean ($\mu$), width ($\sigma$), and raw yield ($S$) of the signal peak are reported together with their statistical uncertainties resulting from the fit. The fraction of non-prompt candidates in the measured raw yield is reported with its statistical and systematic uncertainties. |  |
Figure 4
Prompt and non-prompt $\Ds$ meson production yield in central and semicentral Pb--Pb collisions at $\sqrtsNN = 5.02 \TeV$. The prompt $\Ds$ results are taken from Ref. and scaled by a factor 10 for visibility. The vertical bars (boxes) report the statistical (systematic) uncertainties. |  |
Figure 5
The $\pt$-differential production yield of non-prompt $\Ds$ mesons divided by those of prompt $\Ds$ mesons (left panel) and non-prompt $\Dzero$ mesons (right panel) for the 0-10% and 30-50% centrality intervals in Pb--Pb collisions at $\sqrtsNN=5.02$ $\TeV$ from Refs. compared with those in pp collisions at the same centre-of-mass energy from Ref. . |  |
Figure 6
Left panels: prompt (Ref. ) and non-prompt $\Ds$-meson $\RAA$ in central (top) and semicentral (bottom) Pb--Pb collisions at $\sqrtsNN = 5.02$ TeV. Right panels: non-prompt $\Ds$- and $\Dzero$-meson (Ref. ) $\RAA$ in central (top) and semicentral (bottom) Pb--Pb collisions at $\sqrtsNN = 5.02$ TeV. The experimental results are compared with the predictions of the TAMU model . Statistical (bars), systematic (boxes), and normalisation (shaded box around unity) uncertainties are shown. |  |
Figure 7
The $\RAA$ of non-prompt $\Ds$ mesons divided by the one of prompt $\Ds$ mesons (left panel) and non-prompt $\Dzero$ mesons (right panel) for the 0--10% and 30--50% centrality intervals in Pb--Pb collisions at $\sqrtsNN=5.02 \TeV$. The measurements are compared with TAMU model predictions . Statistical (bars) and systematic (boxes) uncertainties are shown. |  |