论文标题
提示$ \ mathrm {d}^0 $和$ \ OVERLINE {\ MATHRM {D}}^0 $ MESON AZIMUTHAL异常的测量值
Measurement of prompt $\mathrm{D}^0$ and $\overline{\mathrm{D}}^0$ meson azimuthal asymmetry and search for strong electric fields in PbPb collisions at $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV
论文作者
论文摘要
预计在超级繁殖重离子碰撞中创建的强库仑领域有望在$ \ \ mathrm {d}^0 $ {$ \ \ \ \ bar {$ {$ {$ {$ {u} $ {u} $ {u} c}之间，在$ \ mathrm {d}^0 $ \ mathrm {d}之间，在$ \ mathrm {d}之间产生速度依赖性差异（$ΔV_2$）。 $ \ OVILLINE {\ MATHRM {D}}^0 $（$ \ MATHRM {U \ bar {C}} $）Mesons。通过寻找该领域的证据的动机，LHC处的CMS检测器用于执行$ΔV_2$的首次测量。发现快速度平均值为$ \langleδv_2\ rangle = $ 0.001 $ \ pm $ 0.001（stat）$ \ pm $ 0.003（syst）在$ \ sqrt {s_ \ mathrm {nn}} = $ 5.02 = $ 5.02 tev。此外，通过测量$ \ mathrm {d}^0 $和$ \ etlline {\ mathrm {d}}^0 $ ersons $ v_2 $和三角形流量系数（$ v_3 $）作为快速动量，$ p_ \ math（$ p_）的功能（$ p_）（thement）（$ p_）（$ p_）（T）两个Pb核的重叠）。观察到了提示$ \ mathrm {d}^0 $ Meson $ v_2 $值的明显的中心性依赖性，而$ v_3 $在很大程度上独立于中心性。这些趋势与初始状态几何形状驱动的流动期望一致。
The strong Coulomb field created in ultrarelativistic heavy ion collisions is expected to produce a rapidity-dependent difference ($Δv_2$) in the second Fourier coefficient of the azimuthal distribution (elliptic flow, $v_2$) between $\mathrm{D}^0$ ($\mathrm{\bar{u}c}$) and $\overline{\mathrm{D}}^0$ ($\mathrm{u\bar{c}}$) mesons. Motivated by the search for evidence of this field, the CMS detector at the LHC is used to perform the first measurement of $Δv_2$. The rapidity-averaged value is found to be $\langleΔv_2 \rangle =$ 0.001 $\pm$ 0.001 (stat) $\pm$ 0.003 (syst) in PbPb collisions at $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV. In addition, the influence of the collision geometry is explored by measuring the $\mathrm{D}^0$ and $\overline{\mathrm{D}}^0$ mesons $v_2$ and triangular flow coefficient ($v_3$) as functions of rapidity, transverse momentum ($p_\mathrm{T}$), and event centrality (a measure of the overlap of the two Pb nuclei). A clear centrality dependence of prompt $\mathrm{D}^0$ meson $v_2$ values is observed, while the $v_3$ is largely independent of centrality. These trends are consistent with expectations of flow driven by the initial-state geometry.
