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Evidence of rescattering effect in Pb-Pb collisions at the LHC through production of $\rm{K}^{*}(892)^{0}$ and $\phi(1020)$ mesons

The ALICE collaboration
Phys.Lett. B802 (2020) 135225, 2020

Abstract
Measurements of K∗ (892) 0 and φ(1020)resonance production in Pb–Pb and pp collisions at √ sNN = 5.02 TeV with the ALICE detector at the Large Hadron Collider are reported. The resonances are measured at midrapidity (|y| < 0.5) via their hadronic decay channels and the transverse momentum (pT) distributions are obtained for various collision centrality classes up to pT = 20 GeV/c. The pT-integrated yield ratio K∗ (892) 0/K in Pb–Pb collisions shows significant suppression relative to pp collisions and decreases towards more central collisions. In contrast, the φ(1020)/K ratio does not show any suppression. Furthermore, the measured K∗ (892) 0/K ratio in central Pb–Pb collisions is significantly suppressed with respect to the expectations based on a thermal model calculation, while the φ(1020)/K ratio agrees with the model prediction. These measurements are an experimental demonstration of rescattering of K∗ (892) 0 decay products in the hadronic phase of the collisions. The K∗ (892) 0/K yield ratios in Pb–Pb and pp collisions are used to estimate the time duration between chemical and kinetic freeze-out, which is found to be ∼ 4–7 fm/c for central collisions. The pT-differential ratios of K∗ (892) 0/K, φ(1020)/K, K∗ (892) 0/π, φ(1020)/π, p/K ∗ (892) 0 and p/φ(1020) are also presented for Pb–Pb and pp collisions at √ sNN = 5.02 TeV. These ratios show that the rescattering effect is predominantly a low-pT phenomenon.

  • Table 1

    Data from Figure 1 (left panel).

    10.17182/hepdata.93150.v1/t1

    $p_{\rm T}$-distributions of $\rm{K}^{*0}$ (average of particle and anti-particle) meson measured in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV.

  • Table 2

    Data from Figure 1 (left panel).

    10.17182/hepdata.93150.v1/t2

    $p_{\rm T}$-distributions of $\rm{K}^{*0}$ (average of particle and anti-particle) meson measured in pp collisions at $\sqrt{s}$ = 5.02 TeV.

  • Table 3

    Data from Figure 1 (right panel).

    10.17182/hepdata.93150.v1/t3

    $p_{\rm T}$-distributions of $\phi$ meson measured in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV.

  • Table 4

    Data from Figure 1 (right panel).

    10.17182/hepdata.93150.v1/t4

    $p_{\rm T}$-distributions of $\phi$ meson measured in pp collisions at $\sqrt{s}$ = 5.02 TeV.

  • Table 5

    Data from Figure 2.

    10.17182/hepdata.93150.v1/t5

    $p_{\rm T}$-integrated yield ratio of $\rm{K}^{*0}$ (average of particle and anti-particle) to K (average of particle and anti-particle) measured in...

  • Table 6

    Data from Figure 2.

    10.17182/hepdata.93150.v1/t6

    $p_{\rm T}$-integrated yield ratio of $\rm{K}^{*0}$ (average of particle and anti-particle) to K (average of particle and anti-particle) measured in...

  • Table 7

    Data from Figure 2.

    10.17182/hepdata.93150.v1/t7

    $p_{\rm T}$-integrated yield ratio of $\phi$ to K (average of particle and anti-particle) measured in Pb-Pb collisions at $\sqrt{s_{NN}}$ =...

  • Table 8

    Data from Figure 2.

    10.17182/hepdata.93150.v1/t8

    $p_{\rm T}$-integrated yield ratio of $\phi$ to K (average of particle and anti-particle) measured in pp collisions at $\sqrt{s}$ =...

  • Table 9

    Data from Figure 4 (left panel).

    10.17182/hepdata.93150.v1/t9

    $p_{\rm T}$ differential ratio $(\rm{K}^{*0} + \bar{\rm{K}}^{*0}) / (\rm{K}^{+}+\rm{K}^{-})$ measured in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV.

  • Table 10

    Data from Figure 4 (left panel).

    10.17182/hepdata.93150.v1/t10

    $p_{\rm T}$ differential ratio $(\rm{K}^{*0} + \bar{\rm{K}}^{*0}) / (\rm{K}^{+}+\rm{K}^{-})$ measured in pp collisions at $\sqrt{s}$ = 5.02 TeV.

  • Table 11

    Data from Figure 4 (right panel).

    10.17182/hepdata.93150.v1/t11

    $p_{\rm T}$ differential ratio $(2\phi) / (\rm{K}^{+}+\rm{K}^{-})$ measured in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV.

  • Table 12

    Data from Figure 4 (right panel).

    10.17182/hepdata.93150.v1/t12

    $p_{\rm T}$ differential ratio $(2\phi) / (\rm{K}^{+}+\rm{K}^{-})$ measured in pp collisions at $\sqrt{s}$ = 5.02 TeV.

  • Table 13

    Data from Figure 5 (left panel).

    10.17182/hepdata.93150.v1/t13

    $p_{\rm T}$ differential ratio $(\rm{K}^{*0} + \bar{\rm{K}}^{*0}) / (\pi^{+}+\pi^{-})$ measured in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV.

  • Table 14

    Data from Figure 5 (left panel).

    10.17182/hepdata.93150.v1/t14

    $p_{\rm T}$ differential ratio $(\rm{K}^{*0} + \bar{\rm{K}}^{*0}) / (\pi^{+}+\pi^{-})$ measured in pp collisions at $\sqrt{s}$ = 5.02 TeV.

  • Table 15

    Data from Figure 5 (right panel).

    10.17182/hepdata.93150.v1/t15

    $p_{\rm T}$ differential ratio $(2\phi) / (\pi^{+}+\pi^{-})$ measured in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV.

  • Table 16

    Data from Figure 5 (right panel).

    10.17182/hepdata.93150.v1/t16

    $p_{\rm T}$ differential ratio $(2\phi) / (\pi^{+}+\pi^{-})$ measured in pp collisions at $\sqrt{s}$ = 5.02 TeV.

  • Table 17

    Data from Figure 6 (left panel).

    10.17182/hepdata.93150.v1/t17

    $p_{\rm T}$ differential ratio $(\rm{p} + \bar{\rm p}) / (\rm{K}^{*0} + \bar{\rm{K}}^{*0})$ measured in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 5.02...

  • Table 18

    Data from Figure 6 (left panel).

    10.17182/hepdata.93150.v1/t18

    $p_{\rm T}$ differential ratio $(\rm{p} + \bar{\rm p}) / (\rm{K}^{*0} + \bar{\rm{K}}^{*0})$ measured in pp collisions at $\sqrt{s}$ = 5.02...

  • Table 19

    Data from Figure 6 (right panel).

    10.17182/hepdata.93150.v1/t19

    $p_{\rm T}$ differential ratio $(\rm{p} + \bar{\rm p}) / (2\phi)$ measured in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV.

  • Table 20

    Data from Figure 6 (right panel).

    10.17182/hepdata.93150.v1/t20

    $p_{\rm T}$ differential ratio $(\rm{p} + \bar{\rm p}) / (2\phi)$ measured in pp collisions at $\sqrt{s}$ = 5.02 TeV.

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