CMS-PAS-HIN-16-007

CMS-PAS-HIN-16-007
$\mathrm{D}^{0}$ meson $v_{n}$ harmonics in PbPb collisions at 5.02 TeV
CMS Collaboration
September 2016

Abstract: The Fourier coefficients $v_{2}$ and $v_{3}$ , which reflect the azimuthal anisotropy of $\mathrm{D}^{0}$ meson, is measured with scalar-product method in PbPb collisions at $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV with CMS. The measurement is done in a wide $p_{\mathrm{T}}$ range up to 40 GeV/ $c$ , for centrality classes 0-10%, 10-30% and 30-50%. It is the first measurement on $\mathrm{D}^{0}$ $v_{3}$ and the uncertainties on $\mathrm{D}^{0}$ $v_{2}$ are significantly improved compared with previous measurements. The measured $\mathrm{D}^{0}$ $v_{n}$ (n = 2, 3) is consistent with charged particle $v_{n}$ in central collisions, and begins to be lower than charged particles $v_{n}$ in $p_{\mathrm{T}}$ range 1 to 6 GeV/ $c$ for more peripheral collisions. In high $p_{\mathrm{T}}$ range, non-zero $\mathrm{D}^{0}$ $v_{2}$ is also observed, which indicates the path length dependent energy loss of charm quark.
Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ; These preliminary results are superseded in this paper, PRL 120 (2018) 202301. The superseded preliminary plots can be found here.

Figures & Tables	Summary	Additional Figures	References	CMS Publications

Figures
png pdf	Figure 1: Examples of simultaneous fit on mass spectrum and $v_{2}$ (top) or $v_{3}$ (bottom) as a function of invariant mass in selected ${p_{\mathrm {T}}}$ intervals.
png pdf	Figure 1-a: Example of simultaneous fit on mass spectrum and $v_{2}$ as a function of invariant mass in selected ${p_{\mathrm {T}}}$ intervals.
png pdf	Figure 1-b: Example of simultaneous fit on mass spectrum and $v_{2}$ as a function of invariant mass in selected ${p_{\mathrm {T}}}$ intervals.
png pdf	Figure 1-c: Example of simultaneous fit on mass spectrum and $v_{3}$ as a function of invariant mass in selected ${p_{\mathrm {T}}}$ intervals.
png pdf	Figure 1-d: Example of simultaneous fit on mass spectrum and $v_{3}$ as a function of invariant mass in selected ${p_{\mathrm {T}}}$ intervals.
png pdf	Figure 2: Prompt ${\mathrm {D}^{0}}$ fractions in raw ${\mathrm {D}^{0}}$ yield as function of ${p_{\mathrm {T}}}$ for centrality classes 0-10% (left), 10-30% (middle) and 30-50% (right) with all analysis cuts (red circles) and without $b_{0} <$ 0.008 cm cut (blue squares).
png pdf	Figure 3: Prompt ${\mathrm {D}^{0}}$ $v_{2}$ for centrality 0-10% (left), 10-30% (middle) and 30-50% (right). Charged particle $v_{2}$ [21] in the same centrality class is also plotted for comparison.
png pdf	Figure 4: Prompt ${\mathrm {D}^{0}}$ $v_{3}$ for centrality 0-10% (left), 10-30% (middle) and 30-50% (right). Charged particle $v_{3}$ [21] in the same centrality class is also plotted for comparison.

Tables
png pdf	Table 1: Summary of systematic uncertainties for $v_{2}$ and $v_{3}$ for centrality class 30-50%. Absolute uncertainties are assigned.

Summary

In summary, azimuthal anisotropy

$v_2$ and

$v_3$ of

$\mathrm{D}^0$ is measured with scalar-product method in PbPb collisions at

$\sqrt{s_\mathrm{NN}} =$ 5.02 TeV with CMS, which is the first measurement on

$v_3$ of

$\mathrm{D}^0$ . To extract

$v_2$ and

$v_3$ of prompt

$\mathrm{D}^0$ , the systematic uncertainties from non-prompt

$\mathrm{D}^0$ are studied in a data driven method. Prompt

$\mathrm{D}^0$

$v_2$ is found to be positive in studied

$p_{\mathrm{T}}$ range 1 to 40 GeV/

$c$ , and prompt

$\mathrm{D}^0$

$v_3$ is also found to be positive in

$p_{\mathrm{T}}$ range around 1 to 8 GeV/c. The measured prompt

$\mathrm{D}^0$

$v_n$ (

$n =$ 2, 3) is consistent with charged particle

$v_n$ in central collisions, and is lower than

$v_n$ of charged particles in

$p_{\mathrm{T}}$ range 1 to 6 GeV/

$c$ for more peripheral collisions.

Additional Figures
png pdf	Additional Figure 1: Mass spectrum fit in ${p_{\mathrm {T}}}$ intervals 2-3 GeV/ $c$ (a) and 20-40 GeV/ $c$ (b) for centrality 0-10%.
png pdf	Additional Figure 1-a: Mass spectrum fit in ${p_{\mathrm {T}}}$ interval 2-3 GeV/ $c$ for centrality 0-10%.
png pdf	Additional Figure 1-b: Mass spectrum fit in ${p_{\mathrm {T}}}$ interval 20-40 GeV/ $c$ for centrality 0-10%.
png pdf	Additional Figure 2: Mass spectrum fit in ${p_{\mathrm {T}}}$ intervals 1-2 GeV/ $c$ (a), 2-3 GeV/ $c$ (b) and 20-40 GeV/ $c$ (c) for centrality 10-30%.
png pdf	Additional Figure 2-a: Mass spectrum fit in ${p_{\mathrm {T}}}$ interval 1-2 GeV/ $c$ for centrality 10-30%.
png pdf	Additional Figure 2-b: Mass spectrum fit in ${p_{\mathrm {T}}}$ interval 2-3 GeV/ $c$ for centrality 10-30%.
png pdf	Additional Figure 2-c: Mass spectrum fit in ${p_{\mathrm {T}}}$ interval 20-40 GeV/ $c$ for centrality 10-30%.
png pdf	Additional Figure 3: Mass spectrum fit in ${p_{\mathrm {T}}}$ intervals 1-2 GeV/ $c$ (a), 2-3 GeV/ $c$ (b) and 20-40 GeV/ $c$ (c) for centrality 30-50%.
png pdf	Additional Figure 3-a: Mass spectrum fit in ${p_{\mathrm {T}}}$ interval 1-2 GeV/ $c$ for centrality 30-50%.
png pdf	Additional Figure 3-b: Mass spectrum fit in ${p_{\mathrm {T}}}$ interval 2-3 GeV/ $c$ for centrality 30-50%.
png pdf	Additional Figure 3-c: Mass spectrum fit in ${p_{\mathrm {T}}}$ interval 20-40 GeV/ $c$ for centrality 30-50%.
png pdf	Additional Figure 4: Example of template fit on impact parameter distributions to evaluate prompt ${\mathrm {D}^{0}}$ fraction in PbPb collisions in ${p_{\mathrm {T}}}$ interval 5-6 GeV/ $c$ for centrality 10-30%.
png pdf	Additional Figure 5: Example of $\mathrm{d}^{2}N$ /( $\mathrm{d} {p_{\mathrm {T}}} \mathrm{d} \Delta \phi$ ) fit for $v_{2}^{obs}$ with $\Delta \phi$ bins method in ${p_{\mathrm {T}}}$ interval 5-6 GeV/ $c$ for centrality 10-30%.
png pdf	Additional Figure 6: Prompt ${\mathrm {D}^{0}}$ fractions for centrality 0-10% (left), 10-30% (middle) and 30-50% (right) with all analysis cuts.
png pdf	Additional Figure 7: Prompt ${\mathrm {D}^{0}}$ $v_{2}$ for centrality 0-10% (left), 10-30% (middle) and 30-50% (right).
png pdf	Additional Figure 8: Prompt ${\mathrm {D}^{0}}$ $v_{3}$ for centrality 0-10% (left), 10-30% (middle) and 30-50% (right).
png pdf	Additional Figure 9: ${\mathrm {D}^{0}}$ $v_{2}$ from SP method and $\Delta \phi$ bins method for centrality 0-10% (left), 10-30% (middle) and 30-50% (right).
png pdf	Additional Figure 10: ${\mathrm {D}^{0}}$ $v_{3}$ from SP method and $\Delta \phi$ bins method for centrality 0-10% (left), 10-30% (middle) and 30-50% (right).
png pdf	Additional Figure 11: Prompt ${\mathrm {D}^{0}}$ $v_{2}$ for centrality 0-10% (left), 10-30% (middle) and 30-50% (right). Calculations from theoretical models (PRC 94 014909 (2016), PLB 735 (2014) 445, JHEP 1602 (2016) 169 and PRD 91 074027 (2015)) are plotted for comparison. Charged particle $v_{2}$ in the same centrality class is also plotted for comparison.
png pdf	Additional Figure 12: Prompt ${\mathrm {D}^{0}}$ $v_{3}$ for centrality 0-10% (left), 10-30% (middle) and 30-50% (right). Calculations from LBT model (PRC 94 014909 (2016)) are plotted for comparison. Charged particle $v_{3}$ in the same centrality class is also plotted for comparison.
png pdf	Additional Figure 13: Prompt ${\mathrm {D}^{0}}$ $v_{2}$ for centrality 0-10% (a), 10-30% (b) and 30-50% (c). Calculations from theoretical models (PRC 94 014909 (2016), PLB 735 (2014) 445, JHEP 1602 (2016) 169 and PRD 91 074027 (2015)) are plotted for comparison. Charged particle $v_{2}$ in the same centrality class is also plotted for comparison.
png pdf	Additional Figure 13-a: Prompt ${\mathrm {D}^{0}}$ $v_{2}$ for centrality 0-10%. Calculations from theoretical models (PRC 94 014909 (2016), PLB 735 (2014) 445, JHEP 1602 (2016) 169 and PRD 91 074027 (2015)) are plotted for comparison. Charged particle $v_{2}$ in the same centrality class is also plotted for comparison.
png pdf	Additional Figure 13-b: Prompt ${\mathrm {D}^{0}}$ $v_{2}$ for centrality 10-30%. Calculations from theoretical models (PRC 94 014909 (2016), PLB 735 (2014) 445, JHEP 1602 (2016) 169 and PRD 91 074027 (2015)) are plotted for comparison. Charged particle $v_{2}$ in the same centrality class is also plotted for comparison.
png pdf	Additional Figure 13-c: Prompt ${\mathrm {D}^{0}}$ $v_{2}$ for centrality 30-50%. Calculations from theoretical models (PRC 94 014909 (2016), PLB 735 (2014) 445, JHEP 1602 (2016) 169 and PRD 91 074027 (2015)) are plotted for comparison. Charged particle $v_{2}$ in the same centrality class is also plotted for comparison.
png pdf	Additional Figure 14: Prompt ${\mathrm {D}^{0}}$ $v_{3}$ for centrality 0-10% (a), 10-30% (b) and 30-50% (c). Calculations from LBT model (PRC 94 014909 (2016)) are plotted for comparison. Charged particle $v_{3}$ in the same centrality class is also plotted for comparison.
png pdf	Additional Figure 14-a: Prompt ${\mathrm {D}^{0}}$ $v_{3}$ for centrality 0-10%. Calculations from LBT model (PRC 94 014909 (2016)) are plotted for comparison. Charged particle $v_{3}$ in the same centrality class is also plotted for comparison.
png pdf	Additional Figure 14-b: Prompt ${\mathrm {D}^{0}}$ $v_{3}$ for centrality 10-30%. Calculations from LBT model (PRC 94 014909 (2016)) are plotted for comparison. Charged particle $v_{3}$ in the same centrality class is also plotted for comparison.
png pdf	Additional Figure 14-c: Prompt ${\mathrm {D}^{0}}$ $v_{3}$ for centrality 30-50%. Calculations from LBT model (PRC 94 014909 (2016)) are plotted for comparison. Charged particle $v_{3}$ in the same centrality class is also plotted for comparison.
png pdf	Additional Figure 15: Prompt ${\mathrm {D}^{0}}$ $v_{2}$ compared with ALICE results (PRC 90 (2014) 034904) for centrality 0-10% (left), 10-30% (middle) and 30-50% (right).

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