In heavy-ion physics, measurements of short-lived hadronic resonances allow the properties of the hadronic phase of the collision to be studied. In addition, resonances can be used along with stable ...hadrons to study parton energy loss in the quark-gluon plasma and the mechanisms that shape hadron pT spectra at intermediate transverse momenta. Resonance measurements in small systems serve as a reference for heavy-ion collisions and contribute to searches for collective effects. An overview of recent results on hadronic resonance production measured in ALICE is presented. These results include the pT spectra and yields of the ρ(770)0, K*(892)0, and φ(1020) mesons in pp, p-Pb, and Pb-Pb collisions at different energies as well as the Σ(1385)± and Ξ (1530)0 baryons in pp and p-Pb collisions.
Using the EPOS3 model with the Ultrarelativistic Quantum Molecular Dynamics (UrQMD) model to describe the hadronic phase, we study the production of short-lived hadronic resonances and the ...modification of their yields and pT spectra in p-Pb collisions at √sNN= 5.02 TeV. High-multiplicity p-Pb collisions exhibit similar behavior to midperipheral Pb-Pb collisions at LHC energies, and we find indications of a short-lived hadronic phase in p-Pb collisions that can modify resonance yields and pT spectra through scattering processes. The evolution of resonance production is investigated as a function of the system size, which is related to the lifetime of the hadronic phase in order to study the onset and evolution of scattering effects in p-Pb collisions. We also study hadron production separately in the core and corona parts of these collisions and explore how this division affects the total particle yields as the system size increases.
Hadronic resonances serve as unique probes in the study of the hot and dense nuclear matter produced in heavy-ion collisions. Properties of the hadronic phase of the collision can be extracted from ...measurements of the suppression of resonance yields. A comparison of the transverse-momentum spectra of the φ(1020) meson and the proton (which have similar masses) can be used to study particle production mechanisms. Resonance measurements in pp collisions provide input for tuning QCD-inspired particle production models and serve as reference measurements for other collision systems. Measurements of resonances in p-Pb collisions allow nuclear effects in the absence of a hot and dense final state to be studied. The ALICE Collaboration has measured resonances in pp, p-Pb, and Pb-Pb collisions. These measurements will be discussed and compared to results from other experiments and to theoretical models.
Properties of the hadronic phase of high-energy heavy-ion collisions can be studied by measuring the ratios of hadronic resonance yields to the yields of longer-lived particles. These ratios can be ...used to study the strength of re-scattering effects, the chemical freeze-out temperature, and the lifetime between chemical and kinetic freeze-out. The restoration of chiral symmetry during the early hadronic phase or near the phase transition may lead to shifts in the masses and increases in the widths of hadronic resonances. The ALICE collaboration has measured the spectra, masses, and widths of the K*(892)0 and φ(1020) resonances in Pb-Pb collisions at 2.76 TeV. These results, including RAA and the ratios of the integrated resonance yields to stable hadron yields, are presented and compared to results from other collision systems and to theoretical predictions.
The aim of this paper is to understand resonance production (and more generally particle production) for different collision systems, namely proton-proton (pp), proton-nucleus (pA), and ...nucleus-nucleus (AA) scattering at the LHC. We will investigate in particular particle yields and ratios versus multiplicity, using the same multiplicity definition for the three different systems, in order to analyse in a compact way the evolution of particle production with the system size and the origin of a very different system size dependence of the different particles.
Resonances play a unique role in the study of ultra-relativistic heavy-ion collisions. Resonance yields, which may be modified by rescattering and regeneration after hadronization, can be used to ...study the properties of the hadronic phase of the collision. The transversemomentum spectra of the proton and the ϕ(1020) can be used to study the mechanisms of particle production. In addition, resonance measurements in pp and p–Pb collisions help to distinguish initial-state effects from the effects of the hot and dense final state. The ALICE Collaboration has studied the K*(892)0 and ϕ(1020) mesons in pp, p–Pb, and Pb–Pb collisions. Measurements of many resonance properties, including pT spectra, integrated yields, masses, widths, mean pT values, and the nuclear modification factors RAA and RpPb, are presented and compared to measurements from other experiments, non-resonances, and the predictions of theoretical models.
Measurements of the yields of hadronic resonances (relative to non-resonances) in high-energy heavy-ion collisions allow the chemical freeze-out temperature and the time between chemical and thermal ...freeze-out of the collision system to be studied, while modifications to resonance masses and widths could be a signature of chiral symmetry restoration. The spectra (for pT < 5 GeV/c), total integrated yields, ratios to non-resonances (φ/π and φ/K), mass, and width of the φ(1020) meson and the uncorrected yields, mass, and width of the K*(892)0 and mesons have been measured using the ALICE detector for Pb-Pb collisions at TeV. These measurements will be compared to results from other collision systems and energies. Angular correlations between leading trigger hadrons and φ(1020) mesons have been measured in Pb-Pb and pp collisions; the mass and width of the φ(1020) meson as a function of the correlation angle will be presented.
Here, we report a systematic measurement of cumulants, Cn, for net-proton, proton, and antiproton multiplicity distributions, and correlation functions, κn, for proton and antiproton multiplicity ...distributions up to the fourth order in Au+Au collisions at √sNN = 7.7, 11.5, 14.5, 19.6, 27, 39, 54.4, 62.4, and 200 GeV. The Cn and κn are presented as a function of collision energy, centrality and kinematic acceptance in rapidity, y, and transverse momentum, pT. The data were taken during the first phase of the Beam Energy Scan (BES) program (2010–2017) at the BNL Relativistic Heavy Ion Collider (RHIC) facility. The measurements are carried out at midrapidity (|y| < 0.5) and transverse momentum 0.4 < pT < 2.0GeV/c, using the STAR detector at RHIC. We observe a nonmonotonic energy dependence (√sNN = 7.7–62.4 GeV) of the net-proton C4/C2 with the significance of 3.1σ for the 0–5% central Au+Au collisions. This is consistent with the expectations of critical fluctuations in a QCD-inspired model. Thermal and transport model calculations show a monotonic variation with √sNN. For the multiparticle correlation functions, we observe significant negative values for a two-particle correlation function, κ2, of protons and antiprotons, which are mainly due to the effects of baryon number conservation. Furthermore, it is found that the four-particle correlation function, κ4, of protons plays a role in determining the energy dependence of proton C4/C1 below 19.6 GeV, which cannot be understood by the effect of baryon number conservation.
Hadronic resonances at ALICE Knospe, A G
Journal of physics. Conference series,
01/2013, Letnik:
446, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Measurements of the ratios of hadronic resonance yields to non-resonance yields can be used to study the properties of the hadronic phase of high-energy heavy-ion collisions. A change in resonance ...masses or widths could be an indication of chiral symmetry restoration. Measurements of resonances in proton-proton collisions provide an important baseline for measurements in heavy-ion collisions as well as data for tuning QCD-inspired particle production models. The ALICE collaboration has measured the K*(892)0 and φ(1020) resonances in Pb–Pb collisions at 2.76 TeV and the K*(892)0, φ(1020), and Σ*(1385)± resonances in pp collisions at 7 TeV. These measurements – including transverse momentum spectra, ratios to non-resonances, masses, and widths – are discussed and compared to theoretical predictions.
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