The production of K∗(892)± meson resonance is measured at midrapidity (|y| < 0.5) in Pb-Pb collisions at √sNN = 5.02 TeV using the ALICE detector at the CERN Large Hadron Collider. The resonance is reconstructed via its hadronic decay channel K∗(892)± → K0 S π±. The transverse momentum distributions are obtained for various centrality intervals in the pT range of 0.4-16 GeV/c. Measurements of integrated yields, mean transverse momenta, and particle yield ratios are reported and found to be consistent with previous ALICE measurements for K∗(892)0 within uncertainties. The pT-integrated yield ratio 2 K∗(892)±/(K+ + K−) in central Pb-Pb collisions shows a significant suppression at a level of 9.3σ relative to pp collisions. Thermal model calculations result in an overprediction of the particle yield ratio. Although both hadron resonance gas in partial chemical equilibrium (HRG-PCE) and MUSIC + SMASH simulations consider the hadronic phase, only HRG-PCE accurately represents the measurements, whereas MUSIC + SMASH simulations tend to overpredict the particle yield ratio. These observations, along with the kinetic freeze-out temperatures extracted from the yields measured for light-flavored hadrons using the HRG-PCE model, indicate a finite hadronic phase lifetime, which decreases with increasing collision centrality percentile. The pT-differential yield ratios 2 K∗(892)±/(K+ + K−) and 2 K∗(892)±/(π+ + π−) are presented and compared with measurements in pp collisions at √s = 5.02 TeV. Both particle ratios are found to be suppressed by up to a factor of five at pT < 2.0 GeV/c in central Pb-Pb collisions and are qualitatively consistent with expectations for rescattering effects in the hadronic phase. The nuclear modification factor (RAA ) shows a smooth evolution with centrality and is found to be below unity at pT > 8 GeV/c, consistent with measurements for other light-flavored hadrons. The smallest values are observed in most central collisions, indicating larger energy loss of partons traversing the dense medium.
K*(892)+/- resonance production in Pb-Pb collisions at √sNN = 5.02 TeV
Camerini, P.;Contin, G.;De Martin, C.;Fragiacomo, E.;Luparello, G.;Margagliotti, G. V.;Piano, S.;Rui, R.;Villani, A.;Zaccolo, V.;
2024-01-01
Abstract
The production of K∗(892)± meson resonance is measured at midrapidity (|y| < 0.5) in Pb-Pb collisions at √sNN = 5.02 TeV using the ALICE detector at the CERN Large Hadron Collider. The resonance is reconstructed via its hadronic decay channel K∗(892)± → K0 S π±. The transverse momentum distributions are obtained for various centrality intervals in the pT range of 0.4-16 GeV/c. Measurements of integrated yields, mean transverse momenta, and particle yield ratios are reported and found to be consistent with previous ALICE measurements for K∗(892)0 within uncertainties. The pT-integrated yield ratio 2 K∗(892)±/(K+ + K−) in central Pb-Pb collisions shows a significant suppression at a level of 9.3σ relative to pp collisions. Thermal model calculations result in an overprediction of the particle yield ratio. Although both hadron resonance gas in partial chemical equilibrium (HRG-PCE) and MUSIC + SMASH simulations consider the hadronic phase, only HRG-PCE accurately represents the measurements, whereas MUSIC + SMASH simulations tend to overpredict the particle yield ratio. These observations, along with the kinetic freeze-out temperatures extracted from the yields measured for light-flavored hadrons using the HRG-PCE model, indicate a finite hadronic phase lifetime, which decreases with increasing collision centrality percentile. The pT-differential yield ratios 2 K∗(892)±/(K+ + K−) and 2 K∗(892)±/(π+ + π−) are presented and compared with measurements in pp collisions at √s = 5.02 TeV. Both particle ratios are found to be suppressed by up to a factor of five at pT < 2.0 GeV/c in central Pb-Pb collisions and are qualitatively consistent with expectations for rescattering effects in the hadronic phase. The nuclear modification factor (RAA ) shows a smooth evolution with centrality and is found to be below unity at pT > 8 GeV/c, consistent with measurements for other light-flavored hadrons. The smallest values are observed in most central collisions, indicating larger energy loss of partons traversing the dense medium.Pubblicazioni consigliate
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