Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · nucl-ex/0606026

Elliptic flow of Lambda hyperons in Pb+Pb collisions at 158A GeV

G. Stefanek
View original source ↗Read source document ↗Export metadata ↓

Abstract

The elliptic flow of Lambda hyperons has been measured by the NA49 collaboration at the CERN-SPS in semi-central Pb+Pb collisions at 158A GeV. The standard method of correlating particles with the event plane was used. Measurements of v2 near mid-rapidity are reported as a function of rapidity, centrality and transverse momentum. Elliptic flow of Lambda particles increases both with the impact parameter and with the transverse momentum. It is compared with v2 for pions and protons as well as with model calculations. The observation of significant elliptic flow and its mass dependence suggest strong collective behaviour of the matter produced in collisions of heavy nuclei already at the SPS. Scaling properties of elliptic flow of different particle species have been tested at 158A GeV. The limited pT range of the data does not allow for a decisive test of the coalescence model.

Explore related subjects

nucl-ex

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

G. Stefanek. 2007-01-17. Elliptic flow of Lambda hyperons in Pb+Pb collisions at 158A GeV. https://doi.org/10.1103/physrevc.75.044901

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Large amplification of the isospin-dependence of proton emitting source size in nuclear collisions induced by radioactive ion beams: A signal of n-p correlation

We report proton-proton correlation function measurements in central $^{132}$Sn+$^{124}$Sn and $^{108}$Sn+$^{112}$Sn collisions at 270 MeV/nucleon. The proton emitting source sizes are extracted for the systems by using femtoscopic imaging technique. The fast dynamic core radius for the neutron-rich system is found to be $2.22 \pm 0.13\ \text{(stat.)} \pm 0.07\ \text{(syst.)}$ fm, which is approximately 24\% larger than that for the neutron-deficient system, $1.74 \pm 0.08\ \text{(stat.)} \pm 0.05\ \text{(syst.)}$ fm. This difference is an order of magnitude larger than the $\sim$3\% difference in the ground-state charge radii of the projectile nuclei. Transport model simulations based on mean-field dynamics cannot reproduce this amplification. The observation reveals a beyond-mean-field mechanism associated to short-range neutron-proton correlations, which dynamically enhance the proton emitting source in the neutron-rich environment. Our results demonstrate that heavy-ion collisions induced by radioactive beam, combined with femtoscopic precision, provide a new hadronic probe of short-range correlation, and that careful treatment of the beyond-mean-field interactions are required in modeling such processes.

nucl-ex↗
arXiv2026

Quarkonium production in light-ion collisions with the ALICE experiment

Quarkonium production has long been considered as one of the golden probes to study the quark-gluon plasma (QGP). In fact, the early production of heavy quarks (ccbar) and (bbbar) makes quarkonia an ideal tool to investigate the evolution of the hot and dense medium produced in ultra-relativistic heavy-ion collisions. In such a medium, quarkonium production is expected to be suppressed due to the screening of the binding potential between the heavy quark and antiquark and/or through in-medium interactions. Moreover, at LHC energies the recombination of uncorrelated charm quarks pairs, namely regeneration, was found to significantly affect charmonium observables, in contraposition to the suppression mechanism. In addition, measurements in smaller collision systems as p-Pb have highlighted the possibility to observe QGP-like effects. In this context, the study of charmonium production in intermediate collision systems, as light-ion collisions, becomes more and more interesting, representing an ideal test ground for the state-of-the art theoretical models. In this contribution the new measurements of charmonium production will be shown using the light-ion collisions data collected for the first time at the LHC in 2025 (oxygen-oxygen (OO), proton-oxygen (pO)). The results will be shown exploiting the forward ALICE rapidity coverage (2.5 < y < 4). Finally, the measurements will be compared with the existing theoretical models.

nucl-ex↗
arXiv2026

Space-time evolution of particle emission in p$-$Pb collisions at $\mathbf{\sqrt{s_{\rm NN}}=~5.02}$ TeV with 3D kaon femtoscopy

The measurement of three-dimensional femtoscopic correlations between identical charged kaons (K$^\pm$K$^\pm$) produced in p$-$Pb collisions at center-of-mass energy per nucleon pair $\sqrt{s{_{\rm NN}}} = 5.02$ TeV with ALICE at the LHC is presented for the first time. This measurement, supplementary to those in pp and Pb$-$Pb collisions, allows understanding the particle-production mechanisms at different charged-particle multiplicities and provides information on the dynamics of the source of particles created in p$-$Pb collisions, for which a general consensus does not yet exist. It is shown that the measured source sizes increase with charged-particle multiplicity and decrease with increasing pair transverse momentum. These trends for K$^\pm$K$^\pm$ are similar to the ones observed earlier in identical charged-pion and K$_{\rm s}^{0}$K$_{\rm s}^{0}$ correlations in Pb$-$Pb collisions at various energies and in $π^\pm π^\pm$ correlations in p$-$Pb collisions at $\sqrt{s{_{\rm NN}}} = 5.02$ TeV. At comparable multiplicity, the source sizes measured in p$-$Pb collisions agree within uncertainties with those observed in pp collisions, and there is an indication that they are smaller than those observed in Pb$-$Pb collisions. The obtained results are also compared with predictions from the hadronic interaction model EPOS 3, which tends to underestimate the source size for the most central collisions and agrees with the data for semicentral and peripheral events. Furthermore, the time of maximal emission for kaons is extracted. It turns out to be comparable with the value obtained in highly peripheral Pb$-$Pb collisions at the same energy, indicating that the kaon emission evolution is similar to that in p$-$Pb collisions.

nucl-ex↗