Resonances as Probes of Heavy-Ion Collisions at ALICE

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 phi(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.Comment: 4 Pages, 1 figure, Proceedings of Hot Quarks 2014, Las Negras, Spain, 21-28 September 2014, to be published in Journal of Physics: Conference Serie

Hadronic resonance production in Pb-Pb collisions at the ALICE experiment

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 (phi/pi and phi/K), mass, and width of the phi(1020) meson and the uncorrected yields, mass, and width of the K*(892)0 and anti-K*(892)0 mesons have been measured using the ALICE detector for Pb-Pb collisions at 2.76 TeV. These measurements will be compared to results from other collision systems and energies. Angular correlations between leading trigger hadrons and phi(1020) mesons have been measured in Pb-Pb and pp collisions; the mass and width of the phi(1020) meson as a function of the correlation angle will be presented.Comment: 10 pages, 9 figures; Proceedings for Nucleus-Nucleus 2012, 21 May-1 June 2012, San Antonio, Texas, USA; Submitted for publication in J. Phys.: Conference Serie

Recent hadronic resonance measurements at ALICE

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 rho(770)0, K*(892)0, and phi(1020) mesons in pp, p-Pb, and Pb-Pb collisions at different energies as well as the Sigma(1385)+/- and Xi(1530)0 baryons in pp and p-Pb collisions.Comment: 4 pages, 3 figures, Proceedings of the 16th International Conference on Strangeness in Quark Matter (SQM 2016), Berkeley, California, USA, 27 June-1 July 2016, to be published in Journal of Physics: Conference Serie

Metastable States in Two-Lane Traffic Flow Models With Slow-To-Start Rule

Using computer simulations, we show that metastable states still occur in two-lane traffic models with slow to start rules. However, these metastable states no longer exist in systems where aggressive drivers (\textit{which do not look back before changing lanes}) are present. Indeed, the presence of only one aggressive driver in the circuit, triggers the breakdown of the high flow states. In these systems, the steady state is unique and its relaxation dynamics should depend on the lane changing probability $p_{ch}$ and the number of aggressive drivers present in the circuit. It is found also that the relaxation time $\tau$ diverges as the form of a power-law : $\tau\propto p_{ch}^{-\beta}, \beta=1$.Comment: 7 pages, 6 figure

Disorder Effects in CA-Models for Traffic Flow

We investigate the effect of quenched disorder in the Nagel-Schreckenberg model of traffic flow. Spatial inhomogenities, i.e. lattice sites where the braking probability is enlarged, are considered as well as particle disorder, i.e. cars of a different maximum velocity. Both types of disorder lead to segregated states.Comment: 6 pages, 4 postscript figures, Proceedings of the conference "Traffic and Granular Flow '97", Duisburg, Germany, October 5-8, 199