Strange Hadron Resonances: Freeze-Out Probes in Heavy-Ion Collisions

Hyperon resonances are becoming an extremely useful tool allowing the study of the properties of hadronic fireballs made in heavy ion collisions. Their yield, compared to stable particles with the same quark composition, depends on hadronization conditions. The resonance's short lifetime makes them ideal probes of the fireball chemical freeze-out mechanisms. An analysis of resonance abundance in heavy ion collisions should be capable of distinguishing between possible hadronization scenarios, in particular between sudden and gradual hadronization. In this paper, we review the existing SPS and RHIC experimental data on resonance production in heavy ion collisions, and discuss in terms of both thermal and microscopic models the yields of the two observed resonances, K* and Lambda(1520). We show how freeze-out properties, namely chemical freeze-out temperature and the lifetime of the interacting hadron phase which follows, can be related to resonance yields. Finally, we apply these methods to SPS and RHIC measurements, discuss the significance and interpretations of our findings, and suggest further measurements which may help in clarifying existing ambiguities.Comment: To appear in the proceedings of Pan American Advanced Studies Institute on New States of Matter in Hadronic Interactions (PASI 2002), Campos do Jordao, Brazil, 7-18 Jan 2002; American Institute of Physics 2002. v2: reference and language correctio

Resonances and fluctuations at SPS and RHIC

We perform an analysis of preliminary data on hadron yields and fluctuations within the Statistical hadronization ansatz. We describe the theoretical disagreements between different statistical models currently on the market, and show how the simultaneous analysis of yields and fluctuations can be used to determine if one of them can be connected to underlying physics. We perform such an analysis on preliminary RHIC and SPS A-A data that includes particle yields, ratios and event by event fluctuations. We show that the equilibrium statistical model can not describe the $K/\pi$ fluctuation measured at RHIC and SPS, unless an unrealistically small volume is assumed. Such small volume then makes it impossible to describe the total particle multiplicity. The non-equilibrium model,on the other hand, describes both the $K/\pi$ fluctuation and yields acceptably due to the extra boost to the $\pi$ fluctuation provided by the high pion chemical potential. We show, however, that both models significantly over-estimate the $p/\pi$ fluctuation measured at the SPS, and speculate for the reason behind this.Comment: Presented at Hot Quarks, 2006 In press, European Physical Journal

SHARE with CHARM

SHARE with CHARM program (SHAREv3) implements the statistical hadronization model description of particle production in relativistic heavy-ion collisions. Given a set of statistical parameters, SHAREv3 program evaluates yields and therefore also ratios, and furthermore, statistical particle abundance fluctuations. The physical bulk properties of the particle source is evaluated based on all hadrons produced, including the fitted yields. The bulk properties can be prescribed as a fit input complementing and/or replacing the statistical parameters. The modifications and improvements in the SHARE suite of programs are oriented towards recent and forthcoming LHC hadron production results including charm hadrons. This SHAREv3 release incorporates all features seen previously in SHAREv1.x and v2.x and, beyond, we include a complete treatment of charm hadrons and their decays, which further cascade and feed lighter hadron yields. This article is a complete and self-contained manual explaining and introducing both the conventional and the extended capabilities of SHARE with CHARM. We complement the particle list derived from the Particle Data Group tabulation composed of up, down, strange $u,d,s$ quarks (including resonances) with hadrons containing charm $c,\bar c$ quarks. We provide a table of the charm hadron decays including partial widths. The branching ratios of each charm hadron decays add to unity, which is achieved by including some charm hadron decay channels based on theoretical consideration in the absence of direct experimental information. A very successful interpretation of all available LHC results has been already obtained using this program.Comment: 41 pages, 5 figures, 3 tables. Associated program available at http://www.physics.arizona.edu/~gtshare/SHARE/share.html (Computer Physics Communications in press

Charmed Hadrons from Strangeness-rich QGP

The yields of charmed hadrons emitted by strangeness rich QGP are evaluated within chemical non-equilibrium statistical hadronization model, conserving strangeness, charm, and entropy yields at hadronization.Comment: 6 pages, 2 figures SQM 2006; the same as J. Phys. G in pres

Resonances and fluctuations of strange particle in 200 GeV Au-Au collisions

We perform an analysis of preliminary data on strange particles yields and fluctuations within the Statistical hadronization model. We begin by describing the theoretical disagreements between different statistical models currently on the market. We then show how the simultaneous analysis of yields and fluctuations can be used to differentiate between the different models, and determine if one of them can be connected to underlying physics. We perform a study on a RHIC 200 GeV data sample that includes stable particles, resonances, and the event-by-event fluctuation of the $K/\pi$ ratio. We show that the equilibrium statistical model can not describe the fluctuation, unless an unrealistically small volume is assumed. Such small volume then makes it impossible to describe the total particle multiplicity. The non-equilibrium model,on the other hand, describes both the $K/\pi$ fluctuation and yields acceptably due to the extra boost to the $\pi$ fluctuation provided by the high pion chemical potential. $\Lambda(1520)$ and $K^*$ abundance is described within error bars, but the $\Sigma^*$ is under-predicted to $\sim$ 1.5 standard deviations. We suggest further measurements that have the potential to test the non-equilibrium model, as well as gauge the effect of re-interactions between hadronization and freeze-out.Comment: References added, equations corrected. As accepted for publication by Journal of Physics

Heavy quarks and the collective properties of hot QCD

After reviewing the evidence that QCD matter at ultrarelativistic energies behaves as a very good fluid, we describe the connection of QCD fluidity to heavy quark observables. We review the way in which heavy quark spectra can place tighter limits on the viscosity of QCD matter. Finally, we show that correlations between flow observables and the event-by-event charm quark abundance ("flavoring") can shed light on the system's equation of state.Comment: Talk given at BEACH2010 conference, Perugia, Italy Published in Nuclear Physics B (proceedings supplement), NUPHBP1364

Universal Flow-Driven Conical Emission in Ultrarelativistic Heavy-Ion Collisions

The double-peak structure observed in soft-hard hadron correlations is commonly interpreted as a signature for a Mach cone generated by a supersonic jet interacting with the hot and dense medium created in ultrarelativistic heavy-ion collisions. We show that it can also arise due to averaging over many jet events in a transversally expanding background. We find that the jet-induced away-side yield does not depend on the details of the energy-momentum deposition in the plasma, the jet velocity, or the system size. Our claim can be experimentally tested by comparing soft-hard correlations induced by heavy-flavor jets with those generated by light-flavor jets.Comment: 4 pages, 3 figure

Lagrangian formulation of relativistic Israel-Stewart hydrodynamics

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOWe rederive relativistic hydrodynamics as a Lagrangian effective theory using the doubled coordinates technique, allowing us to include dissipative terms. We include Navier-Stokes shear and bulk terms, as well as Israel-Stewart relaxation time terms, within this formalism. We show how the inclusion of shear dissipation forces the inclusion of the Israel-Stewart term into the theory, thereby providing an additional justification for the form of this term.We rederive relativistic hydrodynamics as a Lagrangian effective theory using the doubled coordinates technique, allowing us to include dissipative terms. We include Navier-Stokes shear and bulk terms, as well as Israel-Stewart relaxation time terms, within this formalism. We show how the inclusion of shear dissipation forces the inclusion of the Israel-Stewart term into the theory, thereby providing an additional justification for the form of this term.946112FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO2014/13120-7147435/2014-5, 301996/2014-

A percolation transition in Yang-Mills matter at finite number of colours

We examine baryonic matter at quark chemical potential of the order of the confinement scale, \mu_q\sim \lqcd. In this regime, quarks are supposed to be confined but baryons are close to the ``tightly packed limit'' where they nearly overlap in configuration space. We show that this system will exhibit a percolation phase transition {\em when varied in the number of colours} $N_c$: at high $N_c$, large distance correlations at quark level are possible even if the quarks are essentially confined. At low $N_c$, this does not happen. We discuss the relevance of this for dense nuclear matter, and argue that our results suggest a new ``phase transition'', varying $N_c$ at constant $\mu_q$.Comment: Accepted for publication, Physical Review Letters. Title changed from original, "Quarkyonic percolation at finite number of colors", at the request of the edito