Measurements of $\rm{K}^{*}(892)^{0}$ and $\phi(1020)$ resonance production in Pb-Pb and pp collisions at $\sqrt{s_{\rm{NN}}}$ = 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 ($p_{\rm{T}}$) distributions are obtained for various collision centrality classes up to $p_{\rm{T}}$ $=$ 20 GeV$/c$. The $p_{\rm{T}}$-integrated yield ratio $\rm{K}^{*}(892)^{0}/$KinPb−Pbcollisionsshowssignificantsuppressionrelativetoppcollisionsanddecreasestowardsmorecentralcollisions.Incontrast,the$ϕ(1020)/$K ratio does not show any suppression. Furthermore, the measured $\rm{K}^{*}(892)^{0}/$KratioincentralPb−Pbcollisionsissignificantlysuppressedwithrespecttotheexpectationsbasedonathermalmodelcalculation,whilethe$ϕ(1020)/$K ratio agrees with the model prediction. These measurements are an experimental demonstration of rescattering of $\rm{K}^{*}(892)^{0}$ decay products in the hadronic phase of the collisions. The $\rm{K}^{*}(892)^{0}/$KyieldratiosinPb−Pbandppcollisionsareusedtoestimatethetimedurationbetweenchemicalandkineticfreeze−out,whichisfoundtobe$∼$4−7fm$/c$forcentralcollisions.The$pT$−differentialratiosof$K∗(892)0/$K, $\phi(1020)/$K,$K∗(892)0/\pi$, $\phi(1020)/π$,$p/\rm{K}^{*}(892)^{0}$ and $p/$$\phi(1020)$ are also presented for Pb-Pb and pp collisions at $\sqrt{s_{\rm{NN}}}$ $=$ 5.02 TeV. These ratios show that the rescattering effect is predominantly a low-$p_{\rm{T}}$ phenomenon.
PLB 802 (2020) 135225
HEP Data
e-Print: arXiv:1910.14419 | PDF | inSPIRE
CERN-EP-2019-249